CHAPTER 1
Introduction
The phrase computer science has a very broad meaning today. However, in this book, we
define the phrase as ‘issues related to the computer’. This introductory chapter first tries
to find out what a computer is, then investigates other issues directly related to computers. We look first at the Turing model as a mathematical and philosophical definition of
computation. We then show how today’s computers are based on the von Neumann
model. The chapter ends with a brief history of this culture-changing device . . . the
computer.
Objectives
After studying this chapter, the student should be able to:
Define the Turing model of a computer.
❑ Define the von Neumann model of a computer.
❑ Describe the three components of a computer: hardware, data, and software.
❑ List topics related to computer hardware.
❑ List topics related to data.
❑ List topics related to software.
❑ Give a short history of computers.
❑
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Introduction
1.1
TURING MODEL
The idea of a universal computational device was first described by Alan Turing in 1936.
He proposed that all computation could be performed by a special kind of a machine, now
called a Turing machine. Although Turing presented a mathematical description of such a
machine, he was more interested in the philosophical definition of computation than in
building the actual machine. He based the model on the actions that people perform
when involved in computation. He abstracted these actions into a model for a computational machine that has really changed the world.
1.1.1
Data processors
Before discussing the Turing model, let us define a computer as a data processor. Using
this definition, a computer acts as a black box that accepts input data, processes the data,
and creates output data (Figure 1.1). Although this model can define the functionality of
a computer today, it is too general. In this model, a pocket calculator is also a computer
(which it is, in a literal sense).
Figure 1.1 A single-purpose computing machine
Input data
Computer
Output data
Another problem with this model is that it does not specify the type of processing, or
whether more than one type of processing is possible. In other words, it is not clear how
many types or sets of operations a machine based on this model can perform. Is it a
specific-purpose machine or a general-purpose machine?
This model could represent a specific-purpose computer (or processor) that is designed to do a single job, such as controlling the temperature of a building or controlling
the fuel usage in a car. However, computers, as the term is used today, are general-purpose
machines. They can do many different types of tasks. This implies that we need to change
this model into the Turing model to be able to reflect the actual computers of today.
1.1.2
Programmable data processors
The Turing model is a better model for a general-purpose computer. This model adds an
extra element to the specific computing machine: the program. A program is a set of
instructions that tells the computer what to do with data. Figure 1.2 shows the Turing
model.
In the Turing model, the output data depends on the combination of two factors: the
input data and the program. With the same input data, we can generate different output
if we change the program. Similarly, with the same program, we can generate different
1.1
Turing Model
Figure 1.2 A computer based on the Turing model: programmable data processor
Program
Input data
Computer
Output data
outputs if we change the input data. Finally, if the input data and the program remain the
same, the output should be the same. Let us look at three cases.
Same program, different input data
Figure 1.3 shows the same sorting program with different input data. Although the
program is the same, the outputs are different, because different input data is processed.
Figure 1.3 The same program, different data
Program
3, 12, 8, 22
Input data
Program
14, 6, 8, 12
Input data
Sort
Computer
3, 8, 12, 22
Output data
Sort
Computer
6, 8, 12, 14
Output data
Same input data, different programs
Figure 1.4 shows the same input data with different programs. Each program makes the
computer perform different operations on the input data. The first program sorts the data,
the second adds the data, and the third finds the smallest number.
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4
Introduction
Figure 1.4 The same data, different programs
Program
3, 12, 8, 22
Input data
Sort
Computer
Program
3, 12, 8, 22
Input data
Program
3, 12, 8, 22
Input data
3, 8, 12, 22
Output data
Add
Computer
45
Output data
Find
smallest
Computer
3
Output data
Same input data, same program
We expect the same result each time if both input data and the program are the same, of
course. In other words, when the same program is run with the same input data, we
expect the same output.
1.1.3
The universal Turing machine
A universal Turing machine, a machine that can do any computation if the appropriate
program is provided, was the first description of a modern computer. It can be proved that
a very powerful computer and a universal Turing machine can compute the same thing.
We need only provide the data and the program—the description of how to do the computation—to either machine. In fact, a universal Turing machine is capable of computing
anything that is computable.
1.2
VON NEUMANN MODEL
Computers built on the Turing universal machine store data in their memory. Around
1944–1945, John von Neumann proposed that, since program and data are logically the
same, programs should also be stored in the memory of a computer.
1.2.1
Four subsystems
Computers built on the von Neumann model divide the computer hardware into four
subsystems: memory, arithmetic logic unit, control unit, and input/output (Figure 1.5).
1.2
Von Neumann Model
Figure 1.5 The Von Neumann model
Computer
Input / output
Input
data
Arithmetic logic
unit (ALU)
Memory
Output
data
Control unit
Memory
Memory is the storage area. This is where programs and data are stored during processing.
We discuss the reasons for storing programs and data later in the chapter.
Arithmetic logic unit
The arithmetic logic unit (ALU) is where calculation and logical operations take place.
For a computer to act as a data processor, it must be able to do arithmetic operations on
data (such as adding a list of numbers). It should also be able to do logical operations on
data, as we will see in Chapter 4.
Control unit
The control unit controls the operations of the memory, ALU, and the input/output
subsystem.
Input / output
The input subsystem accepts input data and the program from outside the computer,
while the output subsystem sends the result of processing to the outside world. The definition of the input/output subsystem is very broad: it also includes secondary storage
devices such as disk or tape that stores data and programs for processing. When a disk
stores data that results from processing, it is considered an output device: when it reads
data from the disk, it is considered an input device.
1.2.2
The stored program concept
The von Neumann model states that the program must be stored in memory. This is
totally different from the architecture of early computers in which only the data was
stored in memory: the programs for their task were implemented by manipulating a set of
switches or by changing the wiring system.
The memory of modern computers hosts both a program and its corresponding data.
This implies that both the data and programs should have the same format, because they
are stored in memory. In fact, they are stored as binary patterns in memory—a sequence
of 0s and 1s.
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Introduction
1.2.3
Sequential execution of instructions
A program in the von Neumann model is made of a finite number of instructions. In this
model, the control unit fetches one instruction from memory, decodes it, then executes
it. In other words, the instructions are executed one after another. Of course, one
instruction may request the control unit to jump to some previous or following
instruction, but this does not mean that the instructions are not executed sequentially.
Sequential execution of a program was the initial requirement of a computer based on
the von Neumann model. Today’s computers execute programs in the order that is the
most efficient.
1.3
COMPUTER COMPONENTS
We can think of a computer as being made up of three components: computer hardware,
data, and computer software.
1.3.1
Computer hardware
Computer hardware today has four components under the von Neumann model, although
we can have different types of memory, different types of input/output subsystems, and
so on. We discuss computer hardware in more detail in Chapter 5.
1.3.2
Data
The von Neumann model clearly defines a computer as a data processing machine that
accepts the input data, processes it, and outputs the result.
Storing data
The von Neumann model does not define how data must be stored in a computer. If a
computer is an electronic device, the best way to store data is in the form of an electrical
signal, specifically its presence or absence. This implies that a computer can store data in
one of two states.
Obviously, the data we use in daily life is not just in one of two states. For example,
our numbering system uses digits that can take one of ten states (0 to 9). We cannot (as
yet) store this type of information in a computer: it needs to be changed to another system
that uses only two states (0 and 1). We also need to be able to process other types of data
(text, image, audio, video). These also cannot be stored in a computer directly, but need to
be changed to the appropriate form (0s and 1s).
In Chapter 3, we will learn how to store different types of data as a binary pattern, a
sequence of 0s and 1s. In Chapter 4, we show how data is manipulated, as a binary pattern, inside a computer.
1.3
Computer Components
Organizing data
Although data should be stored only in one form inside a computer, a binary pattern, data
outside a computer can take many forms. In addition, computers (and the notion of data
processing) have created a new field of study known as data organization, which asks the
question: can we organize our data into different entities and formats before storing them
inside a computer? Today, data is not treated as a flat sequence of information. Instead,
data is organized into small units, small units are organized into larger units, and so on. We
will look at data from this point of view in Chapters 11–14.
1.3.3
Computer software
The main feature of the Turing or von Neumann models is the concept of the program.
Although early computers did not store the program in the computer’s memory, they did
use the concept of programs. Programming those early computers meant changing the
wiring systems or turning a set of switches on or off. Programming was therefore a task
done by an operator or engineer before the actual data processing began.
Programs must be stored
In the von Neumann model programs are stored in the computer’s memory. Not only do
we need memory to hold data, but we also need memory to hold the program
(Figure 1.6).
Figure 1.6 Program and data in memory
Program
Data
Memory
A sequence of instructions
Another requirement of the model is that the program must consist of a sequence of
instructions. Each instruction operates on one or more data items. Thus, an instruction can
change the effect of a previous instruction. For example, Figure 1.7 shows a program that
inputs two numbers, adds them, and prints the result. This program consists of four
individual instructions.
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8
Introduction
Figure 1.7 A program made of instructions
1. Input the first number into memory.
2. Input the second number into memory.
3. Add the two together and store the result in memory.
4. Output the result.
Program
We might ask why a program must be composed of instructions. The answer is reusability.
Today, computers do millions of tasks. If the program for each task was an independent
entity without anything in common with other programs, programming would be difficult. The Turing and von Neumann models make programming easier by defining the
different instructions that can be used by computers. A programmer can then combine
these instructions to make any number of programs. Each program can be a different
combination of different instructions.
Algorithms
The requirement for a program to consist of a sequence of instructions made programming
possible, but it brought another dimension to using a computer. A programmer must not
only learn the task performed by each instruction, but also learn how to combine these
instructions to do a particular task. Looking at this issue differently, a programmer must
first solve the problem in a step-by-step manner, then try to find the appropriate instruction
(or series of instructions) to implement those steps. This step-by-step solution is called an
algorithm. Algorithms play a very important role in computer science and are discussed in
Chapter 8.
Languages
At the beginning of the computer age there was only one computer language, machine
language. Programmers wrote instructions (using binary patterns) to solve a problem.
However, as programs became larger, writing long programs using these patterns became
tedious. Computer scientists came up with the idea of using symbols to represent binary
patterns, just as people use symbols (words) for commands in daily life. Of course, the
symbols used in daily life are different from those used in computers. So the concept of
computer languages was born. A natural language such as English is rich and has many
rules to combine words correctly: a computer language, on the other hand, has a more
limited number of symbols and also a limited number of words. We will study computer
languages in Chapter 9.
1.4
History
Software engineering
Something that was not defined in the von Neumann model is software engineering,
which is the design and writing of structured programs. Today it is not acceptable just to
write a program that does a task: the program must follow strict rules and principles. We
discuss these principles, collectively known as software engineering, in Chapter 10.
Operating systems
During the evolution of computers, scientists became aware that there was a series of
instructions common to all programs. For example, instructions to tell a computer where
to receive data and where to send data are needed by almost all programs. It is more
efficient to write these instructions only once for the use of all programs. Thus the concept
of the operating system emerged. An operating system originally worked as a manager to
facilitate access to the computer’s components by a program, although today operating
systems do much more. We will learn about them in Chapter 7.
1.4
HISTORY
In this section we briefly review the history of computing and computers. We divide this
history into three periods.
1.4.1
Mechanical machines (before 1930)
During this period, several computing machines were invented that bear little resemblance
to the modern concept of a computer.
❑ In the seventeenth century, Blaise Pascal, a French mathematician and philosopher,
invented Pascaline, a mechanical calculator for addition and subtraction operations.
In the twentieth century, when Niklaus Wirth invented a structured programming
language, he called it Pascal to honor the inventor of the first mechanical calculator.
❑ In the late seventeenth century, German mathematician Gottfried Leibniz invented a
more sophisticated mechanical calculator that could do multiplication and division as
well as addition and subtraction. It was called the Leibniz Wheel.
❑ The first machine that used the idea of storage and programming was the Jacquard
loom, invented by Joseph-Marie Jacquard at the beginning of the nineteenth century.
The loom used punched cards (like a stored program) to control the raising of the
warp threads in the manufacture of textiles.
❑ In 1823, Charles Babbage invented the Difference Engine, which could do more than
simple arithmetic operations—it could solve polynomial equations, too. Later, he invented a machine called the Analytical Engine that, to some extent, parallels the idea
of modern computers. It had four components: a mill (corresponding to a modern
ALU), a store (memory), an operator (control unit), and output (input/output).
❑ In 1890, Herman Hollerith, working at the US Census Bureau, designed and built
a programmer machine that could automatically read, tally, and sort data stored on
punched cards.
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10
Introduction
1.4.2
The birth of electronic computers (1930–1950)
Between 1930 and 1950, several computers were invented by scientists who could be
considered the pioneers of the electronic computer industry.
Early electronic computers
The early computers of this period did not store the program in memory—all were
programmed externally. Five computers were prominent during these years:
❑ The first special-purpose computer that encoded information electrically was invented by
John V. Atanasoff and his assistant Clifford Berry in 1939. It was called the ABC (Atanasoff Berry Computer) and was specifically designed to solve a system of linear equations.
❑ At the same time, a German mathematician called Konrad Zuse designed a generalpurpose machine called Z1.
❑ In the 1930s, the US Navy and IBM sponsored a project at Harvard University under
the direction of Howard Aiken to build a huge computer called Mark I. This computer used both electrical and mechanical components.
❑ In England, Alan Turing invented a computer called Colossus that was designed to
break the German Enigma code.
❑ The first general-purpose, totally electronic computer was made by John Mauchly and
J. Presper Eckert and was called ENIAC (Electronic Numerical Integrator and Calculator). It was completed in 1946. It used 18 000 vacuum tubes, was 100 feet long by
10 feet high, and weighed 30 tons.
Computers based on the von Neumann model
The preceding five computers used memory only for storing data, and were programmed
externally using wires or switches. John von Neumann proposed that the program and the
data should be stored in memory. That way, every time we use a computer to do a new
task, we need only change the program instead of rewiring the machine or turning
hundreds of switches on and off.
The first computer based on von Neumann’s ideas was made in 1950 at the University of Pennsylvania and was called EDVAC. At the same time, a similar computer called
EDSAC was built by Maurice Wilkes at Cambridge University in England.
1.4.3 Computer generations (1950–present)
Computers built after 1950 more or less follow the von Neumann model. They have
become faster, smaller, and cheaper, but the principle is almost the same. Historians divide
this period into generations, with each generation witnessing some major change in
hardware or software (but not in the model).
First generation
The first generation (roughly 1950–1959) is characterized by the emergence of commercial
computers. During this time, computers were used only by professionals. They were
locked in rooms with access limited only to the operator or computer specialist. Computers
1.5
Computer Science as a Discipline
were bulky and used vacuum tubes as electronic switches. At this time, computers were
affordable only by big organizations.
Second generation
Second-generation computers (roughly 1959–1965) used transistors instead of vacuum
tubes. This reduced the size of computers, as well as their cost, and made them affordable
to small and medium-size corporations. Two high-level programming languages,
FORTRAN and COBOL (see Chapter 9), were invented and made programming easier.
These two languages separated the programming task from the computer operation task.
A civil engineer, for example could write a FORTRAN program to solve a problem
without being involved in the electronic details of computer architecture.
Third generation
The invention of the integrated circuit (transistors, wiring, and other components on a
single chip) reduced the cost and size of computers even further. Minicomputers appeared
on the market. Canned programs, popularly known as software packages, became available.
A small corporation could buy a package, for example for accounting, instead of writing
its own program. A new industry, the software industry, was born. This generation lasted
roughly from 1965 to 1975.
Fourth generation
The fourth generation (approximately 1975–1985) saw the appearance of microcomputers.
The first desktop calculator, the Altair 8800, became available in 1975. Advances in the
electronics industry allowed whole computer subsystems to fit on a single circuit board.
This generation also saw the emergence of computer networks (see Chapter 6).
Fifth generation
This open-ended generation started in 1985. It has witnessed the appearance of laptop
and palmtop computers, improvements in secondary storage media (CD-ROM, DVD, and
so on), the use of multimedia, and the phenomenon of virtual reality.
1.5
COMPUTER SCIENCE AS A DISCIPLINE
With the invention of computers, a new discipline has evolved: computer science. Like any
other discipline, computer science has now divided into several areas. We can divide these
areas into two broad categories: systems areas and applications areas. Systems areas cover
those areas that directly related to the creation of hardware and software, such as computer
architecture, computer networking, security issues, operating systems, algorithms, programming
languages, and software engineering. Applications areas cover those that are related to the
use of computers, such as databases and artificial intelligence. This book is a breadth-first
approach to all of these areas. After reading the book, the reader should have enough
information to select the desired area of specialty.
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CHAPTER 5
Computer Organization
In this chapter we discuss the organization of a stand-alone computer. We explain how
every computer is made up of three subsystems. We also show how a simple, hypothetical
computer can run a simple program to perform primitive arithmetic or logic operations.
Objectives
After studying this chapter, the student should be able to:
List the three subsystems of a computer.
❑ Describe the role of the central processing unit (CPU) in a computer.
❑ Describe the fetch–decode–execute phases of a cycle in a typical computer.
❑ Describe the main memory and its addressing space.
❑ Distinguish between main memory and cache memory.
❑ Define the input/output subsystem.
❑ Understand the interconnection of subsystems and list different bus systems.
❑ Describe different methods of input/output addressing.
❑ Distinguish the two major trends in the design of computer architecture.
❑ Understand how computer throughput can be improved using pipelining.
❑ Understand how parallel processing can improve the throughput of computers.
❑
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Computer Organization
5.1
INTRODUCTION
We can divide the parts that make up a computer into three broad categories or subsystems: the central processing unit (CPU), the main memory, and the input/output subsystem. The next three sections discuss these subsystems and how they are connected to
make a standalone computer. Figure 5.1 shows the three subsystems of a standalone
computer.
Figure 5.1 Computer hardware (subsystems)
Memory
Central Processing Unit
(CPU)
Input / output subsystem
5.2
CENTRAL PROCESSING UNIT
The central processing unit (CPU) performs operations on data. In most architectures it
has three parts: an arithmetic logic unit (ALU), a control unit, and a set of registers,
(Figure 5.2).
Figure 5.2 Central processing unit (CPU)
Registers
R0
R1
R2
ALU
Rn
PC
Control Unit
IR
Central Processing Unit (CPU)
R: Register
PC: Program Counter
IR: Instruction Register
5.2
5.2.1
Central Processing Unit
The arithmetic logic unit (ALU)
The arithmetic logic unit (ALU) performs logic, shift, and arithmetic operations on data.
Logic operations
We discussed several logic operations, such as NOT, AND, OR, and XOR, in Chapter 4.
These operations treat the input data as bit patterns and the result of the operation is also
a bit pattern.
Shift operations
We discussed two groups of shift operations on data in Chapter 4: logical shift operations
and arithmetic shift operations. Logical shift operations are used to shift bit patterns to the
left or right, while arithmetic operations are applied to integers. Their main purpose is to
divide or multiply integers by two.
Arithmetic operation
We discussed some arithmetic operations on integers and reals on Chapter 4. We mentioned that some operations can be implemented more efficiently in hardware.
5.2.2
Registers
Registers are fast stand-alone storage locations that hold data temporarily. Multiple
registers are needed to facilitate the operation of the CPU. Some of these registers are
shown in Figure 5.2.
Data registers
In the past computers had only a few data registers to hold the input data and the result
of the operations. Today, computers use dozens of registers inside the CPU to speed up
their operations, because complex operations are done using hardware instead of software.
These require several registers to hold the intermediate results. Data registers are named
R1 to Rn in Figure 5.2.
Instruction registers
Today computers store not only data, but also programs, in their memory. The CPU is
responsible for fetching instructions one by one from memory, storing them in the instruction register (IR in Figure 5.2), decoding them, and executing them. We will discuss this
issue later in the chapter.
Program counter
Another common register in the CPU is the program counter (PC in Figure 5.2). The
program counter keeps track of the instruction currently being executed. After execution
of the instruction, the counter is incremented to point to the address of the next instruction in memory.
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Computer Organization
5.2.3
The control unit
The third part of any CPU is the control unit. The control unit controls the operation of
each subsystem. Controlling is achieved through signals sent from the control unit to
other subsystems.
5.3
MAIN MEMORY
Main memory is the second major subsystem in a computer (Figure 5.3). It consists of a
collection of storage locations, each with a unique identifier, called an address. Data is
transferred to and from memory in groups of bits called words. A word can be a group of
8 bits, 16 bits, 32 bits, or 64 bits (and growing). If the word is 8 bits, it is referred to as a
byte. The term ‘byte’ is so common in computer science that sometimes a 16-bit word is
referred to as a 2-byte word, or a 32-bit word is referred to as a 4-byte word.
Figure 5.3 Main memory
Address
0000000000 0111001011001100
Contents (values)
0000000001 0000001111001101
0000000010 1110101011101100
1111111111 0000001011111100
Memory
5.3.1
Address space
To access a word in memory requires an identifier. Although programmers use a name to
identify a word (or a collection of words), at the hardware level each word is identified by
an address. The total number of uniquely identifiable locations in memory is called the
address space. For example, a memory with 64 kilobytes and a word size of 1 byte has an
address space that ranges from 0 to 65 535.
Table 5.1 shows the units used to refer to memory. Note that the terminology is misleading: it approximates the number of bytes in powers of 10, but the actual number of
bytes is in powers of 2. Units in powers of 2 facilitates addressing.
Table 5.1 Memory units
Unit
Exact Number of Bytes
Approximation
kilobyte
210 (1024) bytes
103 bytes
megabyte
220 (1 048 576) bytes
106 bytes
gigabyte
230 (1 073 741 824) bytes
109 bytes
terabyte
240 bytes
1012 bytes
5.3
Main Memory
Addresses as bit patterns
Because computers operate by storing numbers as bit patterns, a memory address is also
represented as a bit pattern. So if a computer has 64 kilobytes (216) of memory with a
word size of 1 byte, we need a bit pattern of 16 bits to define an address. Recall from
Chapter 3 that addresses can be represented as unsigned integers (we do not have negative addresses). In other words, the first location is referred to as address 0000000000000000
(address 0), and the last location is referred to as address 1111111111111111 (address
65535). In general, if a computer has N words of memory, we need an unsigned integer of
size log2 N bits to refer to each memory location.
Memory addresses are defined using unsigned binary integers.
Example 5.1
A computer has 32 MB (megabytes) of memory. How many bits are needed to address
any single byte in memory?
Solution
The memory address space is 32 MB, or 225 (25 × 220). This means that we need log2 225, or
25 bits, to address each byte.
Example 5.2
A computer has 128 MB of memory. Each word in this computer is eight bytes. How many
bits are needed to address any single word in memory?
Solution
The memory address space is 128 MB, which means 227. However, each word is eight (23)
bytes, which means that we have 224 words. This means that we need log2 224, or 24 bits,
to address each word.
5.3.2
Memory types
Two main types of memory exist: RAM and ROM.
RAM
Random access memory (RAM) makes up most of the main memory in a computer. In
a random access device, a data item can be accessed randomly—using the address of the
memory location—without the need to access all data items located before it. However,
the term is confusing, because ROM can also be accessed randomly. What distinguishes
RAM from ROM is that RAM can be read from and written to. The CPU can write something to RAM and later overwrite it. Another characteristic of RAM is that it is volatile: the
information (program or data) is lost if the computer is powered down. In other words, all
information in RAM is erased if you turn off the computer or if there is a power outage.
RAM technology is divided into two broad categories: SRAM and DRAM.
SRAM
Static RAM (SRAM) technology uses traditional flip-flop gates (see Appendix E) to hold
data. The gates hold their state (0 or 1), which means that data is stored as long as the
power is on and there is no need to refresh memory locations. SRAM is fast but expensive.
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Computer Organization
DRAM
Dynamic RAM (DRAM) technology uses capacitors, electrical devices that can store
energy, for data storage. If a capacitor is charged, the state is 1; if it is discharged, the state
is 0. Because a capacitor loses some of its charge with time, DRAM memory cells need to
be refreshed periodically. DRAMs are slow but inexpensive.
ROM
The contents of read-only memory (ROM) are written by the manufacturer, and the CPU
can read from, but not write to, ROM. Its advantage is that it is nonvolatile—its contents are
not lost if you turn off the computer. Normally, it is used for programs or data that must
not be erased or changed even if you turn off the computer. For example, some computers
come with ROM that holds the boot program that runs when we switch on the computer.
PROM
One variation of ROM is programmable read-only memory (PROM). This type of memory is blank when the computer is shipped. The user of the computer, with some special
equipment, can store programs on it. When programs are stored, it behaves like ROM and
cannot be overwritten. This allows a computer user to store specific programs in PROM.
EPROM
A variation of PROM is erasable programmable read-only memory (EPROM). It can be
programmed by the user, but can also be erased with a special device that applies ultraviolet
light. To erase EPROM memory requires physical removal and reinstallation of the EPROM.
EEPROM
A variation of EPROM is electrically erasable programmable read-only memory
(EEPROM). EEPROM can be programmed and erased using electronic impulses without
being removed from the computer.
5.3.3
Memory hierarchy
Computer users need a lot of memory, especially memory that is very fast and inexpensive. This demand is not always possible to satisfy—very fast memory is usually not cheap.
A compromise needs to be made. The solution is hierarchical levels of memory (Figure 5.4).
The hierarchy is based on the following:
Figure 5.4 Memory hierarchy
More costly
Fastest
Registers
Cache memory
Main memory
Less costly
Slowest
5.4
❑
❑
❑
Input/Output Subsystem
Use a very small amount of costly high-speed memory where speed is crucial. The
registers inside the CPU are of this type.
Use a moderate amount of medium-speed memory to store data that is accessed often.
Cache memory, discussed next, is of this type.
Use a large amount of low-speed memory for data that is accessed less often. Main
memory is of this type.
5.3.4
Cache memory
Cache memory is faster than main memory but slower than the CPU and its registers.
Cache memory, which is normally small in size, is placed between the CPU and main
memory (Figure 5.5).
Figure 5.5 Cache memory
CPU
Memory
ALU
Control Unit
Cache
Cache memory at any time contains a copy of a portion of main memory. When the CPU
needs to access a word in main memory, it follows this procedure:
1. The CPU checks the cache.
2. If the word is there, it copies the word: if not, the CPU accesses main memory and
copies a block of memory starting with the desired word. This block replaces the previous contents of cache memory.
3. The CPU accesses the cache and copies the word.
This procedure can expedite operations; if the word is in the cache, it is accessed immediately. If the word is not in the cache, the word and a whole block are copied to the cache.
Since it is probable that the CPU, in its next cycle, will need to access the words following
the first word, the existence of the cache speeds processing.
We might wonder why cache memory is so efficient despite its small size. The answer
lies in the ‘80–20 rule’. It has been observed that most computers typically spend 80 per
cent of their time accessing only 20 per cent of the data. In other words, the same data is
accessed over and over again. Cache memory, with its high speed, can hold this 20 per
cent to make access faster at least 80 per cent of the time.
5.4
INPUT/OUTPUT SUBSYSTEM
The third major subsystem in a computer is the collection of devices referred to as the
input/output (I/O) subsystem. This subsystem allows a computer to communicate with
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Computer Organization
the outside world, and to store programs and data even when the power is off. Input/output
devices can be divided into two broad categories: nonstorage and storage devices.
5.4.1
Nonstorage devices
Nonstorage devices allow the CPU/memory to communicate with the outside world, but
they cannot store information.
Keyboard and monitor
Two of the more common nonstorage input/output devices are the keyboard and the
monitor. The keyboard provides input, the monitor displays output and at the same time
echoes input typed on the keyboard. Programs, commands, and data are input or output
using strings of characters. The characters are encoded using a code such as ASCII
(see Appendix A). Other devices that fall in this category are mice, joysticks, and so on.
Printer
A printer is an output device that creates a permanent record. A printer is a nonstorage
device because the printed material cannot be directly entered into a computer again
unless someone retypes or scans it.
5.4.2
Storage devices
Storage devices, although classified as I/O devices, can store large amounts of information
to be retrieved at a later time. They are cheaper than main memory, and their contents are
nonvolatile—that is, not erased when the power is turned off. They are sometimes referred
to as auxiliary storage devices. We can categorize them as either magnetic or optical.
Magnetic storage devices
Magnetic storage devices use magnetization to store bits of data. If a location is
magnetized, it represents 1, if not magnetized, it represents 0.
Magnetic disks
A magnetic disk consists of one or more disks stacked on top of each other. The disks are
coated with a thin magnetic film. Information is stored on and retrieved from the surface
of the disk using a read/write head for each magnetized surface of the disk. Figure 5.6
shows the physical layout of a magnetic disk drive and the organization of a disk.
Figure 5.6 A magnetic disk
Track
Disk
Sector
Controller
98
Disk
Read / write
heads
a. Disk drive
Intertrack
gap
Intersector
gap
b. Tracks and Sectors
5.4
❑
❑
❑
Input/Output Subsystem
Surface organization. To organize data stored on the disk, each surface is divided into
tracks, and each track is divided into sectors (Figure 5.6). The tracks are separated by
an intertrack gap, and the sectors are separated by an intersector gap.
Data access. A magnetic disk is considered a random access device. In a random access
device, a data item can be accessed randomly without the need to access all other data
items located before it. However, the smallest storage area that can be accessed at one
time is a sector. A block of data can be stored in one or more sectors and retrieved
without the need to retrieve the rest of the information on the disk.
Performance. The performance of a disk depends on several factors, the most important being the rotational speed, the seek time, and the transfer time. The rotational
speed defines how fast the disk is spinning. The seek time defines the time to move
the read/write head to the desired track where the data is stored. The transfer time
defines the time to move data from the disk to the CPU/memory.
Magnetic tape
Magnetic tape comes in various sizes. One common type is half-inch plastic tape coated
with a thick magnetic film. The tape is mounted on two reels and uses a read/write head
that reads or writes information when the tape is passed through it. Figure 5.7 shows the
mechanical configuration of a magnetic tape drive.
Figure 5.7 Magnetic tape
Tape reel
Take-up reel
Track 1
Tape
Block
Block
Tape
Track 9
Read / write head
a. Tape drive
❑
❑
❑
b. Surface orgnization
Surface organization. The width of the tape is divided into nine tracks, each location
on a track storing 1 bit of information. Nine vertical locations can store 8 bits of information related to a byte plus a bit for error detection (Figure 5.7).
Data access. A magnetic tape is considered a sequential access device. Although the surface may be divided into blocks, there is no addressing mechanism to access each block.
To retrieve a specific block on the tape, we need to pass through all the previous blocks.
Performance. Although magnetic tape is slower than a magnetic disk, it is cheaper.
Today, people use magnetic tape to back up large amounts of data.
Optical storage devices
Optical storage devices, a relatively recent technology, use laser light to store and retrieve
data. The use of optical storage technology followed the invention of the compact disk (CD)
used to store audio information. Today, the same technology—slightly improved—is used
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Computer Organization
to store information in a computer. Devices that use this technology include CD-ROMs,
CD-Rs, CD-RWs, and DVDs.
CD-ROMs
Compact disk read-only memory (CD-ROM) disks use the same technology as the audio
CD, originally developed by Phillips and Sony for recording music. The only difference
between these two technologies is enhancement: a CD-ROM drive is more robust and
checks for errors. Figure 5.8 shows the steps involved in creating and using a CD-ROM.
Figure 5.8 Creation and use of CD-ROMs
Land
Pit
a. Master disc
b. Mold
Land
Pit
Land
Land
Pit
Pit
Land
Pit Pit
Plastic or glass
Molding material
Label
Protective layer
Reflective layer
c. CD-ROM
Polycarbonate
resin
Laser source
❑
❑
Laser Detector
Creation. CD-ROM technology uses three steps to create a large number of discs:
a. A master disk is created using a high-power infrared laser that creates bit patterns on
coated plastic. The laser translates the bit patterns into a sequence of pits (holes) and
lands (no holes). The pits usually represent 0s and the lands usually represent 1s.
However, this is only a convention, and it can be reversed. Other schemes use a transition (pit to land or land to pit) to represent 1, and a lack of transition to represent 0.
b. From the master disk, a mold is made. In the mold, the pits (holes) are replaced by bumps.
c. Molten polycarbonate resin is injected into the mold to produce the same pits as
the master disk. A very thin layer of aluminum is added to the polycarbonate to
provide a reflective surface. On top of this, a protective layer of lacquer is applied
and a label is added. Only this last step needs to be repeated for each disk.
Reading. The CD-ROM is read using a low-power laser beam. The beam is reflected
by the aluminum surface when passing through a land. It is reflected twice when it
encounters a pit, once by the pit boundary and once by the aluminum boundary. The two
reflections have a destructive effect, because the depth of the pit is chosen to be exactly
5.4
❑
❑
Input/Output Subsystem
one-fourth of the beam wavelength. In other words, the sensor installed in the drive
detects more light when the location is a land and less light when the location is a pit,
so can read what was recorded on the original master disk and copied to the CD-ROM.
Format. CD-ROM technology uses a different format than magnetic disk (Figure 5.9).
The format of data on a CD-ROM is based on:
a. A block of 8-bit data transformed into a 14-bit symbol using an error-correction
method called Hamming code.
b. A frame made up from 42 symbols (14 bits/symbol).
c. A sector made up from 98 frames (2352 bytes).
Speed. CD-ROM drives come in different speeds. Single speed is referred to as 1x,
double speed 2x, and so on. If the drive is single speed, it can read up to 153 600
bytes per second. Table 5.2 shows the speeds and their corresponding data rates.
Table 5.2 CD-ROM speeds
❑
Speed
Data rate
Approximation
1x
153 600 bytes per second
150 KB/s
2x
307 200 bytes per second
300 KB/s
4x
614 400 bytes per second
600 KB/s
6x
921 600 bytes per second
900 KB/s
8x
1 228 800 bytes per second
1.2 MB/s
12x
1 843 200 bytes per second
1.8 MB/s
16x
2 457 600 bytes per second
2.4 MB/s
24x
3 688 400 bytes per second
3.6 MB/s
32x
4 915 200 bytes per second
4.8 MB/s
40x
6 144 000 bytes per second
6 MB/s
Application. The expense involved in creating a master disk, mold, and the actual disk
can be justified if there are a large number of potential customers. In other words, this
technology is economical if the discs are mass produced.
Figure 5.9 CD-ROM format
Byte (8 bit)
Symbol (14 bit)
Frame (42 symbols)
Sector (98 frames)
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Computer Organization
CD-R
Clearly, CD-ROM technology is justifiable only if the manufacturer can create a large number of disks. On the other hand, the compact disk recordable (CD-R) format allows users
to create one or more disks without going through the expense involved in creating CD-ROMs.
It is particularly useful for making backups. You can write once to CD-R disks, but they can
be read many times. This is why the format is sometimes called write once, read many
(WORM).
❑
Creation. CD-R technology uses the same principles as CD-ROM to create a disk
(Figure 5.10). The following lists the differences:
a. There is no master disk or mold.
b. The reflective layer is made of gold instead of aluminum.
c. There are no physical pits (holes) in the polycarbonate: the pits and lands are only
simulated. To simulate pits and lands, an extra layer of dye, similar to the material
used in photography, is added between the reflective layer and the polycarbonate.
d. A high-power laser beam, created by the CD burner of the drive, makes a dark spot
in the dye, changing its chemical composition, which simulates a pit. The areas not
struck by the beam become lands.
❑
❑
❑
Reading. CD-Rs can be read by a CD-ROM or a CD-R drive. This means that any differences should be transparent to the drive. The same low-power laser beam passes in front
of the simulated pits and lands. For a land, the beam reaches the reflective layer and is
reflected. For a simulated pit, the spot is opaque, so the beam cannot be reflected back.
Format and speed. The format, capacity, and speed of CD-Rs are the same as
CD-ROMs.
Application. This technology is very attractive for the creation and distribution of a
small number of disks. It is also very useful for making archive files and backups.
Figure 5.10 Making a CD-R
Label
Protective layer
Reflective layer
Dye
Simulated pit
Polycarbonate
resin
Laser detector
Laser source
CD-RW
Although CD-Rs have become very popular, they can be written to only once. To overwrite
previous materials, a new technology allows a new type of disk called compact disk rewritable (CD-RW). It is sometimes called an erasable optical disk.
5.4
❑
Input/Output Subsystem
Creation. CD-RW technology uses the same principles as CD-R to create the disk
(Figure 5.11). The following lists the differences:
Figure 5.11 Making a CD-RW
Label
Protective Layer
Reflective Layer
Alloy
Amorphous (pit)
Crystalline (land)
Laser detector
❑
❑
❑
❑
Polycarbonate
resin
Laser source
a. Instead of dye, the technology uses an alloy of silver, indium, antimony, and tellurium. This alloy has two stable states: crystalline (transparent) and amorphous
(nontransparent).
b. The drive uses high-power lasers to create simulated pits in the alloy (changing it
from crystalline to amorphous).
Reading. The drive uses the same type of low-power laser beam as CD-ROM and
CD-R to detect pits and lands.
Erasing. The drive uses a medium-power laser beam to change pits to lands. The beam
changes a location from the amorphous state to the crystalline state.
Format and speed. The format, capacity, and speed of CD-RWs are the same as
CD-ROMs.
Application. The technology is definitely more attractive than CD-R technology.
However, CD-Rs are more popular for two reasons. First, blank CD-R discs are less
expensive than blank CD-RW discs. Second, CD-Rs are preferable in cases where the
created disk must not be changed, either accidentally or intentionally.
DVD
The industry has felt the need for digital storage media with even higher capacity. The
capacity of a CD-ROM (650 MB) is insufficient to store video information. The latest
optical memory storage device on the market is called a digital versatile disk (DVD). It
uses a technology similar to CD-ROM, but with the following differences:
a. The pits are smaller: 0.4 microns in diameter instead of the 0.8 microns used
in CDs.
b. The tracks are closer to each other.
c. The beam is a red laser instead of infrared.
d. DVDs use one to two recording layers, and can be single-sided or double-sided.
❑
Capacity. These improvements result in higher capacities (Table 5.3).
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Computer Organization
Table 5.3 DVD capacities
❑
❑
Feature
Capacity
Single-sided, single-layer
4.7 GB
Single-sided, dual-layer
8.5 GB
Double-sided, single-layer
9.4 GB
Double-sided, dual-layer
17 GB
Compression. DVD technology uses MPEG (see Chapter 15) for compression. This
means that a single-sided, single-layer DVD can hold 133 minutes of video at high
resolution. This also includes both audio and subtitles.
Application. Today, the high capacity of DVDs attracts many applications that need
to store a high volume of data.
5.5
SUBSYSTEM INTERCONNECTION
The previous sections outlined the characteristics of the three subsystems (CPU, main
memory, and I/O) in a stand-alone computer. In this section, we explore how these three
subsystems are interconnected. The interconnection plays an important role because
information needs to be exchanged between the three subsystems.
5.5.1
Connecting CPU and memory
The CPU and memory are normally connected by three groups of connections, each called
a bus: data bus, address bus, and control bus (Figure 5.12).
Figure 5.12 Connecting CPU and memory using three buses
CPU
Memory
Data bus
Address bus
Control bus
Data bus
The data bus is made of several connections, each carrying 1 bit at a time. The number of
connections depends on the size of the word used by the computer. If the word is 32 bits
(4 bytes), we need a data bus with 32 connections so that all 32 bits of a word can be
transmitted at the same time.
CHAPTER 20
Social and Ethical Issues
In this chapter, we briefly focus on social and ethical issues related to the use of computers
and to the Internet as a network of computers.
Objectives
After studying this chapter, the student should be able to:
Define three ethical principles related to the use of computers.
❑ Distinguish between physical and intellectual property and list some types of intellectual property.
❑ Define privacy as related to the use of computers.
❑ Give the definition of a computer crime and discuss types of attacks, motivation for
attacks, and how to protect against attacks.
❑ Define hackers and the damage done by them.
❑
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Social and Ethical Issues
20.1
ETHICAL PRINCIPLES
One of the ways to evaluate our responsibility towards the rest of the world when using a
computer is to base our decisions on ethics. Ethics is a very complex subject that would
take several books to describe in detail. In this chapter, we discuss only three principles
that can be related to our goal, shown in Figure 20.1.
Figure 20.1 Three main principles of ethics
Moral Rules
Ethical
Principles
Utilization
Social Contract
20.1.1
Moral rules
The first ethical principle states that when we make an ethical decision, we need to consider if the decision is made in accordance with a universally accepted principle of morality. For example, if we want to illegally access a computer to get some information, we
need to ask ourselves if this act is moral. We know that most people in the world do not
consider such actions to be moral, which means that we would be ignoring the first principle of ethics if we acted in this way.
The first principle of ethics says that we should avoid doing anything
if it is against universal morality.
20.1.2
Utilization
The second theory of ethics is related to the consequences of the act. An act is ethical if it
results in consequences which are useful for society. If a person accesses a bank’s computer and erases customer records, is this act useful for society? Since this action may
damage the financial status of the bank’s customer, it is detrimental to society. It does not
bring about a good result. It is not ethical.
The second principle of ethics says that an act is ethical if it
brings about a good result.
20.1.3
Social contract
The social contract theory says that an act is ethical when a majority of people in society
agrees with it. If someone breaks into somebody else’s house and commits a robbery, does
this act receive the approval of a majority of society? Since the answer is negative, this act
is not ethical.
20.2
Intellectual Property
The third principle of ethics says an act is ethical if a majority
of people in society agree with it.
20.2
INTELLECTUAL PROPERTY
Most ethical issues in the past were related to physical property. Physical property has
been defined and physical property rights have been recognized by society throughout
history. If a person has a physical object, such as a computer, the rights to this property are
granted to the owner. It has been proved that ignoring physical property rights may affect
the three ethical principles discussed above.
Modern societies have gone further and have recognized the right to intellectual
property. For example, an author should be given the right to benefit from his/her written
book. An artist should be given the right to benefit from his/her artwork. However, there
are some differences between the two types of property:
1. A physical property cannot be copied; it needs to be manufactured or built. If we
need another computer, we need to physically build it. On the other hand, intellectual property can be copied. We can make a copy of a book without rewriting it.
2. Copying intellectual property still leaves the owner with the original. Stealing a computer deprives the owner of its use.
3. The owner of intellectual property is only one person (or a group); many people can
have the same physical property.
20.2.1
Types of intellectual property
Modern societies have recognized several types of intellectual property: trademarks, trade
secrets, patents, and copyright.
Trademarks
A trademark identifies a company’s product or service. A trademark is an intellectual
property right granted by the government for a limited term, but which can be renewed.
A trademark is considered intellectual property in that the corresponding product cannot
legally be copied by other companies or individuals.
Trade secrets
A trade secret is the information about a product that is kept secret by the owner. For
example, a company can create a product but keep the formula secret. A programmer can
create a piece of software, but keep the program code secret. People can use the product
or the software, but they do not own the formula or the code. Unlike trademarks, a trade
secret does not have to be registered; the owner just has to keep it secret.
Patents
A patent is a right to a monopoly to use and commercially exploit a piece of intellectual
property for a limited period of time. The owner has the right to give or not to give permission
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528
Social and Ethical Issues
to anyone who wishes to use the invention. However, the individual property needs to have
certain characteristics such as novelty, usefulness, and the capability of being built.
Copyright
A copyright is a right to a written or created work. It gives the author the exclusive rights
to copy, distribute, and display the work. Copyright arises automatically, and does not
need to be applied for or formally registered, but a statement of the creator’s copyright
should be mentioned somewhere on the work.
20.3
PRIVACY
Today, a large amount of personal information about a citizen is collected by private and
public agencies. Although in many cases the collection of this information is necessary, it
may also pose some risks. Some of the information collected by government or private
companies can be used commercially. In many countries, a citizen’s right to privacy is,
directly or indirectly, mentioned in the nation’s constitution. However, there is a conflict
between people’s right to privacy and the need to collect information about them. Usually
governments create a balance between the two through laws. Some countries have introduced codes of ethics related to the use of computers to collect data, as shown below:
1.
2.
3.
4.
5.
6.
Collect only data that are needed.
Be sure that the collected data are accurate.
Allow individuals to know what data have been collected.
Allow individuals to correct the collected data if necessary.
Be sure that collected data are used only for the original purpose.
Use encryption techniques (discussed in Chapter 16) to accomplish private
communication.
20.4
COMPUTER CRIMES
For the purposes of this book, we give a simple definition of a computer crime. A computer crime is an illegal act, called an attack, involving any of the following:
1. A computer
2. A computer network
3. A computer-related device
4. Software
5. Data stored in a computer
6. Documentation related to the use of computers
20.4.1
Types of attacks
Attacks can be divided into two categories: penetration and denial of service.
20.4
Computer Crimes
Penetration attack
Penetration in this case means breaking into a system to get access to the data stored in a
computer or in a computer network. Penetration can result in changing data directly or
injecting viruses, worms, and Trojan horses to alter the data indirectly.
Viruses
Viruses are unwanted programs that are hidden within other programs (host). When
the user executes the host program, the virus takes control and replicates itself by
attaching itself to other programs. Eventually, the multitude of viruses may stop normal
computer operations. Viruses can also be transferred to other machines through the
network.
Worms
A worm is an independent program which can copy itself and which travels through the
network. It is a self-replicating piece of software that can travel from one node to another.
It tries to find weaknesses in the system to inflict harm. It can reproduce many copies of
itself, thus slowing down access to the Internet or stopping communication altogether.
Trojan horses
A Trojan horse is a computer program that does perform a legitimate task, but which also
contains code to carry out malicious attacks such as deleting or corrupting files. It can also
be used to access user passwords or other secret information.
Denial of service attack
The denial of service is an attack on a computer connected to the Internet. These attacks
reduce the capability of a computer system to function correctly or bring the system
down altogether by exhausting its resources.
20.4.2
Motives
Attacks are made with many different motivations such as political reasons, a hacker’s
personal interpretation of computer ethics, terrorism, espionage, financial gain, or hate.
20.4.3
Attack protection
Although attacks cannot be avoided easily, there are some strategies that can be applied
to reduce the number or impact of the attacks. We describe three strategies briefly.
Use physical protection
The computer can be physically protected to allow physical access only to trusted
individuals.
Use protective software
Software can be used to protect your data, such as data encryption or the use of strong
passwords to access the software.
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Social and Ethical Issues
Install strong anti-virus software
Strong anti-virus software can control access to the computer when installing new software or accessing Internet sites.
20.4.4
Cost
It is obvious that ordinary citizens usually bear the cost of these computer attacks. When
private companies spend money on preventing attacks, consumers using their products
pay through increased prices. When government organizations spend money to prevent
attacks, citizens pay through increased taxes.
20.5
HACKERS
The word hacker today has a different meaning than when it was used in the past. Previously, a hacker was a person with a lot of knowledge who could improve a system and
increase its capability. Today, a hacker is someone who gains unauthorized access to a
computer belonging to someone else in order to copy secret information.
Although some of the infiltrations carried out by hackers can be harmless, most countries impose heavy penalties for both harmless and harmful hacking. In most countries,
accessing government computers without authorization is a crime. Moreover, in many
countries there is a heavy punishment for hackers who access the computers of private
institutions, and the simple act of obtaining information from somebody else’s computer
is a crime, whether the information is used or not.
20.6
END-CHAPTER MATERIALS
20.6.1
Recommended reading
For more details about the subjects discussed in this chapter, the following books are
recommended:
❑ Kizza, J. M. Ethical and Social Issues in the Information Age, London: Springer, 2010
❑ Schneider, M and. Gersting, J. L. Invitation to Computer Science, 7th edition, Boston,
MA: Cengage Learning, 2016
❑ Reynold, C. and Tymann, P. Schaum’s Outline of Principles of Computer Science,
New York: McGraw-Hill, 2008
❑ Long, L and Long, N. Computers, Upper Saddle River, NJ: Prentice-Hall, 1999
20.6.2
Key terms
This chapter has introduced the following key terms, which are listed here with the pages
on which they first occur:
copyright 528
privacy 528
denial of service 529
social contract 526
20.7
ethical principle 526
trademark 527
hackers 530
trade secret 527
intellectual property 527
Trojan horse 529
moral rules 526
utilization 526
patent 527
virus 529
penetration attack 529
worm 529
20.6.3
❑
❑
❑
❑
❑
❑
❑
Practice Set
Summary
One of the ways to evaluate our responsibility towards the rest of the world when
using a computer is to base our decisions on ethics using the three principles of moral
rules, utilization, and social contract.
Ethical issues nowadays deal not only with physical property but also with intellectual property.
Four different types of intellectual property are trademarks, trade secrets, patents, and
copyrights.
One major ethical issue of our time is respect of privacy.
Computer crime mostly involves penetration or denial of service attacks on computer
systems.
Computer attacks can be avoided using physical protection, protective software, and
anti-virus software.
The term hacker today refers to a person or organization that gains unauthorized access to a computer belonging to someone else to copy secret information.
20.7
PRACTICE SET
20.7.1
Quizzes
A set of interactive quizzes for this chapter can be found on the book’s website. It is
strongly recommended that the student takes the quizzes to check his/her understanding
of the materials before continuing with the practice set.
20.7.2
Review questions
Q20-1. What are the three principles of ethics discussed in this chapter?
Q20-2. What are some differences between a physical and an intellectual property?
Q20-3. What are some privacy codes of ethics related to using computers?
Q20-4. What is the difference between penetration and denial of service when talking
about computer crimes?
Q20-5. What are the three ways a malicious person can penetrate a computer belonging
to someone else?
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Social and Ethical Issues
20.7.3
Problems
P20-1. Assume you have created a piece of software that can be used by many vendors.
Is this intellectual property protected by a copyright or a patent? Explain your
answer.
P20-2. You have created a piece of software for which you want to keep the code secret.
Do you need to register this intellectual property? Explain your answer.
P20-3. If someone collects data about you without informing you in advance, is this act
against your right to privacy? Explain your answer.
P20-4. If someone sends you an email that carries a virus, what type of computer crime
is committed here? Explain your answer.
P20-5. If someone renders an institution’s computer system so busy that it cannot do any
more work, what type of computer crime is committed? Explain your answer.
P20-6. Explain the difference between a virus and a worm.
P20-7. Explain the difference between a virus and a Trojan horse.
P20-8. Explain the difference between a worm and a Trojan horse.
P20-9. Describe different ways in which you can protect your computer from attacks.
P20-10. Explain the damage that a hacker can inflict on a computer system of a financial
institution.
1
Creating a Worksheet
and a Chart
Objectives
After completing this module, you will be able to:
• Start an app
• Format cells in a worksheet
• Identify the components of the
Microsoft Office ribbon
• Create a pie chart
• Describe the Excel worksheet
• Change a worksheet name and sheet
tab color
• Enter text and numbers
• Change document properties
• Use the Sum button to sum a range
of cells
• Preview and print a worksheet
• Enter a simple function
• Copy the contents of a cell to a range
of cells using the fill handle
• Use the AutoCalculate area to display
statistics
• Correct errors on a worksheet
• Use Microsoft Office Help
• Apply cell styles
Introduction
Almost every organization collects vast amounts of data. Often, data is consolidated
into a summary so that people in the organization better understand the meaning of
the data. An Excel worksheet allows data to be summarized and charted easily. A chart
is a graphic element that illustrates data. In this module, you will create a worksheet
that includes a chart. The data in the worksheet and chart comprise a budget that
contains monthly estimates for each income and expense category.
Project: Real Estate Budget Worksheet and
Chart
The project in this module follows proper design guidelines and uses Excel to create
the worksheet and chart shown in Figure 1–1a and Figure 1–1b. The worksheet
contains budget data for Frangold Realty. Mrs. Frangold has compiled a list of her
projected expenses and sources of income and wants to use this information to
create an easy-to-read worksheet. In addition, she would like a pie chart to show her
estimated monthly expenses by category.
Figure 1–1(a) Real Estate Budget Worksheet
Figure 1–1(b) Pie Chart Showing Monthly Expenses by Category
EX 1-2
The first step in creating an effective worksheet is to make sure you understand
what is required. The person or persons requesting the worksheet may supply their
requirements in a requirements document, or you can create one. A requirements
document includes a needs statement, a source of data, a summary of calculations, and
any other special requirements for the worksheet, such as charting and web support.
Figure 1–2 shows the requirements document for the new workbook to be created in
this module.
Worksheet Title
Frangold Real Estate Budget
Need
A yearly projection of Frangold Realty’s budget
Source of data
Data supplied by Madelyn Frangold includes monthly estimates for income
and expenses
Calculations
The following calculations must be made:
1. For each month, a total for income and expenses
2. For each budget item, a total for the item
3. For the year, total all income and expenses
4. Net income = Total income - Expenses
Why is it important to plan a worksheet?
The key to developing a useful worksheet is careful planning. Careful planning can reduce your effort significantly and result in
a worksheet that is accurate, easy to read, flexible, and useful. When analyzing a problem and designing a worksheet solution,
what steps should you follow?
1. Define the problem, including need, source of data, calculations, charting, and web or special requirements.
2. Design the worksheet.
3. Enter the data and formulas.
4. Test the worksheet.
After carefully reviewing the requirements document (Figure 1–2) and making
the necessary decisions, the next step is to design a solution or draw a sketch of the
worksheet based on the requirements, including titles, column and row headings, the
location of data values, and the pie chart, as shown in Figure 1–3. The dollar signs and
commas that you see in the sketch of the worksheet indicate formatted numeric values.
EX 1-3
CONSIDER THIS
Figure 1–2
EX 1-4 Excel Module 1 Creating a Worksheet and a Chart
Real Estate Budget Worksheet
sketch of
worksheet
and chart
Income
January
December
Total
$99,999.99
$99,999.99
$99,999.99
$99,999.99
$99,999.99
$99,999.99
January
December
Total
$99,999.99
$99,999.99
$99,999.99
Total
$99,999.99
$99,999.99
$99,999.99
Net
$99,999.99
$99,999.99
$99,999.99
Commission
Interest
Total
Expenses
Rent
Utilities
Advertising
Website
Printing
Office Supplies
Gas
Miscellaneous
Monthly Expenses
Legend of Expenses
Figure 1–3
With a good understanding of the requirements document, an understanding of
the necessary decisions, and a sketch of the worksheet, the next step is to use Excel to
create the worksheet and chart.
Starting and Using Excel
What Is Excel?
Excel is a powerful spreadsheet app that allows users to organize data, complete
calculations, make decisions, graph data, develop professional-looking reports, publish
organized data to the web, and access real-time data from websites. The four major
parts of Excel are as follows:
• Workbooks and Worksheets: A workbook is like a notebook. Inside the
workbook are sheets, each of which is called a worksheet. A worksheet is a
single sheet in a workbook file that lets you enter and manipulate data, perform
calculations with data, and analyze data. Thus, a workbook is a collection of
worksheets. Worksheets allow users to enter, calculate, manipulate, and analyze
data, such as numbers and text. The terms “worksheet” and “spreadsheet” are
interchangeable.
• Charts: Excel can draw a variety of charts, such as column charts and pie charts.
• Tables: Tables organize and store data within worksheets. For example, once
a user enters data into a worksheet, an Excel table can sort the data, search for
specific data, and select data that satisfies defined criteria.
• Web Support: Web support allows users to save Excel worksheets or parts of a
worksheet in a format that a user can view in a browser, so that a user can view
and manipulate the worksheet using a browser. Excel web support also provides
access to real-time data, such as stock quotes, using web queries.
To Start Excel and Create a Blank Workbook
Across the bottom of the Windows desktop is the taskbar. The taskbar contains the Start button, a
clickable button at in the lower left corner of the Windows 10 screen that you click to open the Start menu.
The Start menu provides access to all programs, documents, and settings on the computer. The Start menu
may contain one of more folders, and these folders can be used to group related apps together. A folder is an
electronic container that helps you organize your computer files, like a cardboard folder on your desk; it can
contain subfolders for organizing files into smaller groups.
The Start menu allows you to start programs, store and search for documents, customize the computer
or mobile device, and sign out of a user account or shut down the computer or mobile device. A menu is a list
of related items, including folders, programs, and commands. Each command on a menu performs a specific
action, such as saving a file or obtaining help. Why? Commands are one of the principal ways you communicate with
an app so you can tell it what you want it to do.
The following steps, which assume Windows is running, use the Start menu to start Excel and create
a blank workbook based on a typical installation. You may need to ask your instructor how to start Excel on
your computer.
1
•
Click the
Start button on the
Windows taskbar
to display the Start
menu containing a
list of apps installed
on the computer or
mobile device.
Start menu
scroll box
• If necessary, scroll
list of apps installed
on computer (your list
may differ)
to display Excel
(Figure 1–4).
Excel app name
Note: To help you locate screen
elements that are referenced
in the step instructions, such
as buttons and commands, this
book uses red boxes to point
to these screen elements.
Start button
Figure 1–4
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-5
EX 1-6 Excel Module 1 Creating a Worksheet and a Chart
2
• Click Excel to start
the app (Figure 1–5).
Microsoft Excel
is running
Blank workbook
thumbnail, or
miniature image
Figure 1–5
Excel Window
3
• Click the Blank
Q&A
workbook
thumbnail on the
Excel start screen
to create a blank
Excel workbook in
the Excel window
(Figure 1–6).
title bar
blank workbook
created
What happens when
I start Excel?
Excel provides a
means for you
to create a blank
document, as shown
in Figure 1–5.
After you click the
Blank workbook
thumbnail, the Excel
Figure 1–6
window shown in
Figure 1–6 opens. A window is a rectangular-shaped work area that displays an app or a collection of files, folders,
and Windows tools. A window has a title bar, an area at the top of a document window or app window that
displays the file name and program name.
Other Ways
1. Type app name in search box, click app name in results list
2. Double-click file created in app you want to start
The Excel Window
The Excel window consists of a variety of components to make your work more efficient and worksheets
more professional. These include the worksheet window, ribbon, Tell Me box, Quick Access Toolbar, and
Microsoft Account area.
Excel opens a new workbook with one worksheet. If necessary, you can add additional worksheets. Each
worksheet has a sheet name that appears on a sheet tab, an indicator at the bottom of the window that identifies
a worksheet. For example, Sheet1 is the name of the active worksheet displayed in the blank workbook shown in
Figure 1–7. You can add more sheets to the workbook by clicking the New sheet button.
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-7
Worksheet The worksheet is organized into a rectangular grid containing vertical columns and horizontal
rows. A column letter in a box above the grid, also called the column heading, appears above each worksheet
column to identify it. A row number in a box on the left side of a worksheet row, also called the row heading,
identifies each row.
The intersection of each column and row is a cell. A cell is the box, formed by the intersection of a column
and a row, where you enter data. Each worksheet in a workbook has 16,384 columns and 1,048,576 rows for a
total of 17,179,869,184 cells. Only a small fraction of the active worksheet appears on the screen at one time.
A cell is referred to by its unique address, or cell reference, which is the column letter and row number
location that identifies a cell within a worksheet, such as A1. To identify a cell, specify the column letter first,
followed by the row number. For example, cell reference D5 refers to the cell located at the intersection of
column D and row 5 (Figure 1–7).
One cell on the worksheet, designated the active cell, is the worksheet cell into which you are entering
data. The active cell in Figure 1–7 is A1. The active cell is identified in three ways. First, a heavy border
surrounds the cell; second, the active cell reference shows immediately above column A in the Name box;
and third, the column heading A and row heading 1 are highlighted so that it is easy to see which cell is active
(Figure 1–7).
Microsoft
account area
Quick Access
Toolbar
Name
box
ribbon
Tell Me box
heavy
border
surrounding
active cell
column
heading L
cell D5
gridlines
worksheet
window
row heading 12
highlighted row
and column
headings indicate
cell A1 is active
scroll boxes
adjusts size
of displayed
document
sheet tab
scroll bars
New sheet
button
status bar
tab scrolling buttons
View buttons; default
is Normal view
Figure 1–7
scroll arrows
EX 1-8 Excel Module 1 Creating a Worksheet and a Chart
The evenly spaced horizontal and/or vertical lines used in a worksheet or chart are called gridlines.
Gridlines make a worksheet easier to read. If desired, you can turn the gridlines off so that they do not show on
the worksheet. While learning Excel, gridlines help you to understand the structure of the worksheet.
The pointer appears as a block plus sign whenever it is located in a cell on the worksheet. Another
common shape of the pointer is the block arrow. The pointer turns into the block arrow when you move it
outside the worksheet or when you drag cell contents between rows or columns.
Scroll Bars Scroll bars on the right edge (vertical scroll bar) and bottom edge (horizontal scroll bar) of a
document window let you view a document that is too large to fit on the screen at once. You use a scroll bar to
display different portions of a document in the document window. On a scroll bar, the position of the scroll box
reflects the location of the portion of the document that is displayed in the document window.
Status Bar The status bar is the gray bar at the bottom of the Excel window that shows status information
about the currently open worksheet, as well as view buttons and zoom controls. As you type text or perform
certain tasks, various indicators and buttons may appear on the status bar. The right side of the status bar
includes buttons and controls you can use to change the view of a document and adjust the size of the displayed
document.
Ribbon The ribbon (shown in Figure 1–8) is a horizontal strip near the top of the window that contains tabs
(pages) of grouped command buttons that you click to interact with the app. Each tab in the ribbon contains a group
of related commands and settings. Each group is a tab element on the ribbon that contains related commands.
When you start an Office app, such as Excel, it initially displays several main tabs, also called default or top-level
tabs. All Office apps have a Home tab, which contains the more frequently used commands. When you start Excel,
the ribbon displays ten main tabs: File, Home, Insert, Draw, Page Layout, Formulas, Data, Review, View, and Help.
(If you are using a desktop computer, you might not see the Draw tab.)
Home tab
arrow
button
main tabs
groups
scroll box
status bar
scroll bar
status bar controls
Figure 1–8
In addition to the main tabs, Excel displays tool tabs, also called contextual tabs (Figure 1–9), tabs that
appear in addition to the main tabs on the ribbon when you perform certain tasks or work with objects, such as
pictures or tables. If you insert a chart in an Excel workbook, for example, the Chart Tools tab and its related
subordinate Design and Format tabs appear, collectively referred to as the Chart Tools Design tab or the Chart
Tools Format tab. When you are finished working with the chart, the Chart Tools tabs disappear from the
ribbon. Excel determines when tool tabs should appear and disappear based on tasks you perform.
Chart Tools Design tab
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-9
Chart Tools Format tab
gallery
scroll
arrows
More
button
in-ribbon gallery
Figure 1–9
Items on the ribbon include
buttons and galleries (shown in
Figures 1–8 and 1–9). A gallery is
a collection of choices, arranged in
a grid or list, that you can browse
through before making a selection
of items such as fonts. You can
scroll through choices in a gallery
by clicking its scroll arrows. Or, you
can click a gallery’s More button to
view more gallery options on the
screen at a time.
Some buttons and boxes
have arrows that, when clicked,
also display a gallery; others always
cause a gallery to be displayed
when clicked. Most galleries
support live preview, an Office
feature that shows the results that
would occur in your file, such as
the effects of formatting options
on a document’s appearance, if
you clicked the option you are
pointing to (Figure 1–10). Live
preview works only if you are using
a mouse; if you are using a touch
screen, you will not be able to view
live previews.
Chart Tools Design tab is one
of many tool tabs that appear
automatically depending on
the task you perform
as you move pointer
from one gallery option
to next, Excel shows
live preview of chart
design in worksheet, so
that you can see effect
of option in worksheet
before selecting it
chart changes
to style selected
in gallery
Figure 1–10
EX 1-10 Excel Module 1 Creating a Worksheet and a Chart
Some commands on the ribbon display
an image to help you remember their function.
When you point to a command on the ribbon,
all or part of the command glows in a darker
shade of gray, and a ScreenTip appears on the
screen. A ScreenTip (Figure 1–11) is a label
that appears when you point to a button or
object, which may include the name, purpose,
or keyboard shortcut for the object. It may also
include a link to associated Help topics, if any.
Some groups on the ribbon have a small
arrow in the lower-right corner, called a Dialog
Box Launcher, that when clicked displays a
dialog box or a pane with more options for the
group (Figure 1–12). When presented with
a dialog box, you make selections and must
close the dialog box before returning to the
document. A pane, in contrast to a dialog box,
is a section of a window, such as the navigation
pane in the File Explorer window, that can
remain open and visible while you work in the
document.
Quick Access
Toolbar
Touch/Mouse
Mode button
pointer on
Paste arrow
ScreenTip for
Paste arrow
Figure 1–11
clicking Font Dialog Box
Launcher displays Format
Cells dialog box
Font Dialog
Box Launcher
Font group
Figure 1–12
Mini Toolbar The Mini toolbar is a small toolbar that appears automatically next to selected text and that
contains the most frequently used text formatting commands, such as bold, italic, font color, and font size
(Figure 1–13). If you do not use the Mini toolbar,
it disappears from the screen. The buttons,
arrows, and boxes on the Mini toolbar may vary,
depending on whether you are using Touch mode
versus Mouse mode. If you right-click an item
in the document window, Excel displays both
the Mini toolbar and a shortcut menu, which is
discussed in a later section in this module.
All commands on the Mini toolbar also
exist on the ribbon. The purpose of the Mini
toolbar is to minimize hand or mouse movement.
Quick Access
Toolbar
mini toolbar
commands on
mini toolbar also
are on ribbon
Quick Access Toolbar The Quick
Figure 1–13
Access Toolbar (shown in Figure 1–13) is a
customizable toolbar at the left edge of the title bar that contains buttons you can click to perform frequently
used commands. The commands on the Quick Access Toolbar always are available, regardless of the task you are
performing. If your computer or mobile device has a touch screen, the Touch/Mouse Mode button will appear on
the Quick Access Toolbar and will allow you to switch between Touch mode and Mouse mode. If you are primarily
using touch gestures, Touch mode will add more space between commands on menus and on the ribbon so that
they are easier to tap. While touch gestures are convenient ways to interact with Office apps, not all features are
supported when you are using Touch mode. If you are using a mouse, Mouse mode will not add the extra space
between buttons and commands. The Quick Access Toolbar is discussed in more depth later in the module.
KeyTips If you prefer using the keyboard instead of the mouse, you can display KeyTips for certain commands
(Figure 1–14). KeyTips are labels that appear over each tab and command on the ribbon when the ALT key is
pressed. To select a command using the keyboard, press the letter or number displayed in the KeyTip, which
may cause additional KeyTips related to the selected command to appear. To remove KeyTips from the screen,
press the alt key or the esc key until all KeyTips disappear, or click anywhere in the app window.
Formula Bar As you type, Excel displays your entry in the formula bar, the area above the worksheet grid where
you enter or edit data in the active cell (Figure 1–14). You can make the formula bar larger by dragging the bottom
of the formula bar or clicking the expand button to the right of the formula bar. Excel also displays cell information
in the Name box, a box to the left of the formula bar that shows the cell reference or name of the active cell.
Tell Me Box The Tell Me box is a text box to the right of the ribbon tabs that is used to find a command or to
access the Office Help system (Figure 1–14). As you type in the Tell Me box, Excel displays search results that are
refined as you type. For example, if you want to center text in a document, you can type “center” in the Tell Me
box and then select the appropriate command. The Tell Me box also lists related commands and/or the last five
commands accessed from the box.
Microsoft Account Area In the Microsoft Account area, an area on the right side of the title bar, you can use the
Sign in link to sign in to your Microsoft account (Figure 1–14). Once signed in, you will see your account information.
KeyTips appear
when you press ALT
key on keyboard
Tell Me box
Microsoft
Account area
Formula bar
Name box
Figure 1–14
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-11
EX 1-12 Excel Module 1 Creating a Worksheet and a Chart
To Display a Different Tab on the Ribbon
The ribbon tab currently displayed is called the active tab. The following step displays the Insert tab; that
is, it makes it the active tab. Why? When working with an Office app, you may need to switch tabs to access other options
for working with a document.
1
• Click Insert on the ribbon to display the Insert tab (Figure 1–15).
Experiment
• Click the other tabs on the ribbon to view their contents.
• Click the View tab, click the Page Layout tab, and then click the Insert tab again.
Insert tab
‘Collapse the
Ribbon’ button
Insert tab has 9 groups
Figure 1–15
Other Ways
1. Press ALT, press letter corresponding to tab to display
Selecting a Cell
BTW
Touch Mode
Differences
The Office and Windows
interfaces may vary if you are
using touch mode. For this
reason, you might notice that
the function or appearance
of your touch screen differs
slightly from this module’s
presentation.
To enter data into a cell, you first must select it. The easiest way to select a cell (to
make it active) is to use the mouse to move the block plus sign pointer to the cell and
then click.
An alternative method is to use the arrow keys that are located on a standard
keyboard. An arrow key selects the cell adjacent to the active cell in the direction of the
arrow on the key.
You know a cell is selected, or active, when a heavy border surrounds the cell and
the active cell reference appears in the Name box on the left side of the formula bar. Excel
also changes the color of the active cell’s column and row headings to a darker shade.
Entering Text
In Excel, any set of characters containing a letter, hyphen (as in a telephone number),
or space is considered text. Text is used for titles, such as column and row titles, on the
worksheet.
Worksheet titles and subtitles should be as brief and meaningful as possible.
A worksheet title could include the name of the organization, department, or a
description of the content of the worksheet. A worksheet subtitle, if included, could
include a more detailed description of the content of the worksheet. Examples of
worksheet titles are January 2021 Payroll and Year 2021 Projected Budget, and
examples of subtitles are Finance Department and Monthly Projections, respectively.
As shown in Figure 1–16, data in a worksheet is identified by row and column
titles so that the meaning of each entry is clear. Rows typically contain information
such as categories of data. Columns typically describe how data is grouped in the
worksheet, such as by month or by department.
cell address
worksheet title
column button
shaded to indicate it
contains active cell
BTW
Screen Resolution
worksheet subtitle
column
titles
active cell, F20, appears
in the Name box and
has heavy border
row
titles
row button is shaded
to indicate it contains
active cell
If you are using a computer
to step through the project
in this module and you want
your screens to match the
figures in this book, you
should change your screen’s
resolution to 1366 × 768.
block plus
sign
Figure 1–16
To Enter the Worksheet Titles
As shown in Figure 1–16, the worksheet title, Frangold Real Estate Budget, identifies the purpose of the
worksheet. The worksheet subtitle, Monthly Estimates, identifies the type of data contained in the worksheet.
Why? A title and subtitle help the reader to understand clearly what the worksheet contains. The following steps enter
the worksheet titles in cells A1 and A2. Later in this module, the worksheet titles will be formatted so that they
appear as shown in Figure 1–16.
1
• Click Home on the
ribbon to display the
Home tab.
• If necessary, click
cell A1 to make cell
A1 the active cell
(Figure 1–17).
heavy border
indicates cell
A1 is selected
Figure 1–17
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-13
EX 1-14 Excel Module 1 Creating a Worksheet and a Chart
2
• Type Frangold Real
Estate Budget in cell A1
Q&A
(Figure 1–18).
Why did the appearance of the
formula bar change?
Excel displays the title in the
formula bar and in cell A1. When
you begin typing a cell entry,
Excel enables two additional
boxes in the formula bar: The
Cancel button and the Enter
button. Clicking the Enter button
completes an entry. Clicking the
Cancel button cancels an entry.
Enter button
formula bar
cancel button
text in active cell
overflows into adjacent
cells to the right
Figure 1–18
3
• Click the Enter button in the
Q&A
formula bar to complete the entry
and enter the worksheet title
(Figure 1–19).
Why does the entered text appear
in three cells?
When the typed text is longer
than the width of a cell, Excel
displays the overflow characters
in adjacent cells to the right
as long as those adjacent cells
contain no data. If the adjacent
cells contain data, Excel hides the
overflow characters. The overflow
characters are visible in the
formula bar whenever that cell is
active.
Enter button
text entered
in cell A1
Figure 1 –19
4
• Click cell A2 to select it.
• Type Monthly Estimates
as the cell entry.
• Click the Enter button to complete
Q&A
the entry and enter the worksheet
subtitle (Figure 1–20).
What happens when I click the
Enter button?
When you complete an entry by
clicking the Enter button, the
insertion point disappears and the
cell in which the text is entered
remains the active cell.
Enter button
worksheet subtitle
entered in cell A2
Figure 1–20
Other Ways
1. Click any cell other than active cell
2. Press ENTER
3. Press HOME, PAGE UP, PAGE DOWN, END, UP ARROW, DOWN
ARROW, LEFT ARROW, or RIGHT ARROW
AutoCorrect
The AutoCorrect feature of Excel works behind the scenes, where it automatically
detects and corrects typing errors. AutoCorrect makes three types of corrections for you:
1. Corrects two initial uppercase letters by changing the second letter to lowercase.
2. Capitalizes the first letter in the names of days.
3. Replaces commonly misspelled words with their correct spelling. For example,
it will change the misspelled word recieve to receive when you complete the entry.
AutoCorrect will correct the spelling of hundreds of commonly misspelled
words automatically.
BTW
Ribbon and Screen
Resolution
Excel may change how the
groups and buttons within
the groups appear on the
ribbon, depending on the
screen resolution of your
computer. Thus, your ribbon
may look different from the
ones in this book if you are
using a screen resolution
other than 1366 × 768.
To Enter Column Titles
The worksheet is divided into two parts, income and expense, as shown in Figure 1–16. Grouping income
and expense data by month is a common method for organizing budget data. The column titles shown in row 3
identify the income section of the worksheet and indicate that the income values will be grouped by month.
Likewise, row 8 is clearly identified as the expense section and similarly indicates that the expense values will
be estimated on a per-month basis. The following steps enter the column titles in row 3. Why? Data entered in
columns should be identified using column titles to identify what the column contains.
1
• Click cell A3 to make it the active
cell.
• Type Income to begin entry
of a column title in the active cell
(Figure 1–21).
active cell
reference in Name
box changes to A3
Income displayed
in formula bar
and cell A3
cell A3 is
active cell
Figure 1–21
Excel Module 1
Why is it difficult to read the text on my screen?
If you are having trouble reading the cell values in your spreadsheet, you can zoom in to make the cells larger. When you zoom
in, fewer columns and rows display on your screen, and you might have to scroll more often. To zoom in, drag the zoom slider
on the right side of the status bar, or click the plus button on the zoom slider, until you reach your desired zoom level. You also
can zoom by clicking the Zoom button (View tab | Zoom group), selecting a desired zoom percentage (Zoom dialog box), and
then clicking OK (Zoom dialog box).
CONSIDER THIS
Creating a Worksheet and a Chart Excel Module 1 EX 1-15
EX 1-16 Excel Module 1 Creating a Worksheet and a Chart
2
• Press the RIGHT ARROW key to enter the column title and make
Q&A
the cell to the right the active cell (Figure 1–22).
Why is the RIGHT ARROW key used to complete the entry in
the cell?
Pressing an arrow key to complete an entry makes the
adjacent cell in the direction of the arrow (up, down, left,
or right) the next active cell. However, if your next entry is
in a nonadjacent cell, you can complete your current entry
by clicking the next cell in which you plan to enter data. You
also can press ENTER and then click the appropriate cell for
the next entry.
cell B3 is
active cell
column title
entered
Figure 1–22
3
• Repeat Steps 1 and 2 to enter the remaining column titles; that is, enter January in cell B3, February in
March in cell D3, April in cell E3, May in cell F3, June in cell G3, July in cell H3,
August in cell I3, September in cell J3, October in cell K3, November in cell L3, December in
cell M3, and Total in cell N3 (complete the last entry in cell N3 by clicking the Enter button in the formula bar).
cell C3,
• Click cell A8 to select it.
• Repeat Steps 1 and 2 to enter the remaining column titles; that is, enter Expenses in cell A8, January in
cell B8, February in cell C8, March in cell D8, April in cell E8, May in cell F8, June in cell G8,
July in cell H8, August in cell I8, September in cell J8, October in cell K8, November in cell L8,
December in cell M8, and Total in cell N8 (complete the last entry in cell N8 by clicking the Enter button in
the formula bar) (Figure 1–23).
Enter button
column titles
left-aligned
in cells
Figure 1–23
To Enter Row Titles
The next step in developing the worksheet for this project is to enter the row titles in column A. For
the Frangold Real Estate Budget worksheet data, the row titles contain a list of income types and expense
types. Each income or expense item should be placed in its own row. Why? Entering one item per row allows for
maximum flexibility, in case more income or expense items are added in the future. The following steps enter the row
titles in the worksheet.
1
• Click cell A4 to
select it.
• Type Commission
and then click cell
A5 or press the
DOWN ARROW key
to enter a row title
(Figure 1–24).
row title, Commission,
entered in cell A4
cell A5 is
active cell
Figure 1–24
2
• Repeat Step 1 to enter the remaining row titles
Q&A
in column A; that is, enter Interest in cell
A5, Total in cell A6, Rent in cell A9,
Utilities in cell A10, Advertising in
cell A11, Website in cell A12, Printing
in cell A13, Office Supplies in cell A14,
Gas in cell A15, Miscellaneous in cell
A16, Total in cell A17, and Net in cell
A19 (Figure 1–25).
Why is the text left-aligned in the cells?
Excel automatically left-aligns the text
in the cell. Excel treats any
combination of numbers, spaces,
row titles
and nonnumeric characters as
entered
text. For example, Excel would
recognize the following entries as
text: 401AX21, 921–231, 619 321,
883XTY. How to change the text
alignment in a cell is discussed
later in this module.
Figure 1–25
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-17
EX 1-18 Excel Module 1 Creating a Worksheet and a Chart
Entering Numbers
In Excel, you enter a number into a cell to represent an amount or value. A number is an
amount or value using any of the following characters: 1 2 3 4 5 6 7 8 9 + - ( ) , / . $ E e.
The use of special characters is explained when they are used in this book. If you are
entering numbers that will not be used in a calculation, you should format those numbers
as text. You can format numeric data as text by typing an apostrophe before the number(s).
To Enter Numbers
The Frangold Real Estate Budget worksheet numbers used in Module 1 are summarized in Table 1–1.
These numbers, which represent yearly income and expense amounts, are entered in rows 4–5 and 9–16. Why?
One of the most powerful features of Excel is the ability to perform calculations on numeric data. Before you can perform
calculations, you first must enter the data. The following steps enter the numbers in Table 1–1 one row at a time.
Table 1–1 Frangold Real Estate Budget Worksheet
Income
January February March
Commission
Interest
12000
100
Expenses
January February March
12000
100
April
May
June
July
August September October November December
14000 14000 16000 18500 20000
100
100
100
100
100
18500
100
18500
100
14000
100
14000
100
16500
100
April
May
June
July
August September October November December
Rent
Utilities
Advertising
Website
Printing
1500
325
400
0
200
1500
325
400
0
200
1500
325
400
0
200
1500
325
400
0
200
1500
325
400
0
200
1500
325
400
0
200
1500
325
400
500
200
1500
325
400
0
200
1500
325
400
0
200
1500
325
400
0
200
1500
325
400
0
200
1500
325
400
0
200
Office Supplies
Gas
Miscellaneous
200
100
250
0
100
250
0
100
250
200
100
250
0
100
250
0
100
250
200
100
250
0
100
250
0
100
250
200
100
250
0
100
250
0
100
250
1
• Click cell B4 to select it.
• Type 12000 and then press the RIGHT ARROW
Q&A
key to enter the data in the selected cell and
make the cell to the right (cell C4) the active
cell (Figure 1–26).
Do I need to enter dollar signs, commas, or
trailing zeros for the amounts?
You are not required to type dollar signs,
commas, or trailing zeros. When you enter
a dollar value that has cents, however, you
must add the decimal point and the numbers
representing the cents. Later in this module,
you will learn how to format numbers with
dollar signs, commas, and trailing zeros to
improve their appearance and readability.
cell C4 is
active cell
12000 entered
in cell B4
Figure 1–26
2
• Refer to Table 1–1 and enter the appropriate values in cells C4, D4, E4, F4, G4, H4, I4, J4, K4, L4, and M4 to complete
Q&A
the first row of numbers in the worksheet (Figure 1–27).
Why are the numbers right-aligned?
When you enter numeric data in a cell, Excel recognizes the values as numbers and automatically right-aligns the
values in order to vertically align decimal and integer values.
commission
amounts
entered in
row 4
numbers rightaligned in cells
Figure 1–27
3
• Click cell B5 to select it and complete the entry in the previously selected cell.
• Enter the remaining numbers provided in Table 1–1 for each of the nine remaining budget items in row 5 and
rows 9–16 (Figure 1–28).
data entered
in worksheet
some row
titles only
partially
visible
Figure 1–28
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-19
EX 1-20 Excel Module 1 Creating a Worksheet and a Chart
Calculating Sums and Using Formulas
The next step in creating the worksheet is to perform any necessary calculations, such
as calculating the column and row totals. In Excel, you can easily perform calculations
using a function. A function is a special, predefined formula that provides a shortcut
for a commonly used calculation, for example, SUM or COUNT. When you use
functions, Excel performs the calculations for you, which helps to prevent errors and
allows you to work more efficiently.
To Sum a Column of Numbers
As stated in the requirements document in Figure 1–2, totals are required for each month and each budget item.
The first calculation is to determine the total of Commission and Interest income in the month of January (column B).
To calculate this value in cell B6, Excel must add, or sum, the numbers in cells B4 and B5. The SUM function adds all
the numbers in a range of cells. Why? The Excel SUM function is an efficient means to accomplish this task.
Many Excel operations are performed on a range of cells. A range is a series of two or more adjacent cells
in a column, row, or rectangular group of cells, notated using the cell address of its upper left and lower right
corners, such as B5:C10. For example, the group of adjacent cells B4 and B5 is a range.
After calculating the total income for January, you will use the fill handle to calculate the monthly totals
for income and expenses and the yearly total for each budget item. The following steps sum the numbers in
column B.
1
• Click cell B6 to make it the active cell.
• Click the AutoSum button (Home tab | Editing group) to enter a formula in the formula bar and in the active cell
Q&A
(Figure 1–29).
What if my screen displays the Sum menu?
If you are using a touch screen, you may not have a separate AutoSum button and AutoSum arrow. In this case,
select the desired option (Sum) on the AutoSum menu.
How does Excel know which cells to sum?
Excel automatically selects what it considers to be your choice of the range to sum. When proposing the range,
Excel first looks for a range of cells with numbers above the active cell and then to the left. If Excel proposes the
wrong range, you can correct it by dragging through the correct range before pressing ENTER. You also can enter
the correct range by typing the beginning cell reference, a colon (:), and the ending cell reference.
AutoSum button
AutoSum
arrow
SUM function
in formula bar
B4:B5 in parentheses indicates
range to be summed
SUM function displayed in active cell
proposed range to
sum surrounded
by moving border
called a marquee
Figure 1–29
Editing
group
2
Q&A
• Click the Enter button in the formula bar to enter the sum in the active cell.
What is the purpose of the arrow next to the AutoSum button on the ribbon?
The AutoSum arrow (shown in Figure 1–29) displays a list of functions that allow you to easily determine the
average of a range of numbers, the number of items in a selected range, or the maximum or minimum value of a
range.
3
• Repeat Steps 1 and 2 to enter the SUM function in cell B17 (Figure 1–30).
Enter button
SUM function
entered in cell B6
SUM function
entered in cell B17
Figure 1–30
Other Ways
1. Click Insert Function button
in formula bar, select SUM
in Select a function list,
click OK (Insert Function
dialog box),
click OK (Function Arguments
dialog box)
2. Click AutoSum arrow (Home tab |
Editing group), click More Functions
in list, scroll to and
then click SUM (Insert
Function dialog box), click
OK, select range (Function
Arguments dialog box),
click OK
Using the Fill Handle to Copy
a Cell to Adjacent Cells
You want to calculate the income totals for each month in cells C6:M6. Table 1–2
illustrates the similarities between the function and range used in cell B6 and the
function and ranges required to sum the totals in cells C6, D6, E6, F6, G6, H6, I6, J6,
K6, L6, and M6.
To calculate each total for each range across the worksheet, you could follow the
same steps shown previously in Figure 1–29 and Figure 1–30. A more efficient method,
however, would be to copy the SUM function from cell B6 to the range C6:M6. A
range of cells you are cutting or copying is called the source area or copy area. The
range of cells to which you are pasting is called the destination area or paste area.
3. Type =s in cell, select
SUM in list, select range,
click Enter button
4. Press ALT+EQUAL SIGN (=)
twice
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-21
EX 1-22 Excel Module 1 Creating a Worksheet and a Chart
Table 1–2 Sum Function Entries in Row 6
Cell
SUM Function Entries
Result
B6
=SUM(B4:B5)
Sums cells B4 and B5
C6
=SUM(C4:C5)
Sums cells C4 and C5
D6
=SUM(D4:D5)
Sums cells D4 and D5
E6
=SUM(E4:E5)
Sums cells E4 and E5
F6
=SUM(F4:F5)
Sums cells F4 and F5
G6
=SUM(G4:G5)
Sums cells G4 and G5
H6
=SUM(H4:H5)
Sums cells H4 and H5
I6
=SUM(I4:I5)
Sums cells I4 and I5
J6
=SUM(J4:J5)
Sums cells J4 and J5
K6
=SUM(K4:K5)
Sums cells K4 and K5
L6
=SUM(L4:L5)
Sums cells L4 and L5
M6
=SUM(M4:M5)
Sums cells M4 and M5
Although the SUM function entries in Table 1–2 are similar to each other,
they are not exact copies. The range in each SUM function entry uses cell references
that are one column to the right of the previous column. When you copy and paste a
formula that includes a cell reference, Excel uses a relative reference, a cell address
that automatically changes to reflect the new location when the formula is copied or
moved. You will learn more about relative references in Module 2. Table 1–2 shows
how Excel adjusts the SUM functions entries in row 6. Relative referencing is the
default type of referencing used in Excel worksheets.
To Copy a Cell to Adjacent Cells in a Row
The easiest way to copy the SUM formula from cell B6 to cells C6:M6 is to use the fill handle. Why?
Using the fill handle copies content to adjacent cells using one action, which is more efficient than other methods. The fill
handle is a box that appears in the lower-right corner of a selected cell or range. It is used to fill adjacent cells
with duplicate or similar data. The following steps use the fill handle to copy cell B6 to the adjacent cells C6:M6.
1
• With cell B6 active, point to the fill handle; your pointer changes to a crosshair (Figure 1–31).
pointer changes to
crosshair indicating that
you can begin dragging
Figure 1–31
2
• Drag the fill handle
to select the
destination area, the
range C6:M6, which
will draw a heavy
green border around
the source area and
the destination area
(Figure 1–32). Do not
release the mouse
button.
as you drag, Excel displays
border around destination
and source area
source area
destination area
Figure 1–32
3
• Release the mouse
Q&A
button to copy the
SUM function from
the active cell to the
destination area and
calculate the sums
(Figure 1–33).
What is the purpose
of the Auto Fill
Options button?
The Auto Fill Options
button allows you to
choose whether you
want to copy the
values from the
source area to the
destination area
with the existing
formatting, without
the formatting, or
with the formatting
but without the
functions.
heavy border and transparent
gray background indicates
B6:M6 remain selected
‘Auto Fill Options’
button remains on
screen until you
begin next activity
SUM function entered
in range C6:M6
Figure 1–33
4
• Repeat Steps 1–3
to copy the SUM
function from cell
B17 to the range
C17:M17 (Figure
1–34).
SUM function in range C17:M17
Figure 1–34
Other Ways
1. Select source area, click Copy button (Home
tab | Clipboard group), select destination area,
click Paste button (Home tab | Clipboard group)
2. Right-click source area, click Copy on shortcut
menu, select and right-click destination area,
click Paste on shortcut menu
3. Select source and destination areas, click
Fill arrow (Home tab | Editing group),
click Sum
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-23
EX 1-24 Excel Module 1 Creating a Worksheet and a Chart
To Calculate Multiple Totals at the Same Time
The next step in building the worksheet is to determine the total income, total expenses, and total for each
budget item in column N. To calculate these totals, you use the SUM function similarly to how you used it to
total the income and expenses for each month in rows 6 and 17.
In this case, however, Excel will determine totals for all of the rows at the same time. Why? By determining
multiple totals at the same time, the number of steps to add totals is reduced. The following steps sum multiple totals at
once.
1
• Click cell N4 to make it the active cell (Figure 1–35).
pointer is block
plus sign
cell N4 is
active cell
Figure 1–35
2
• With the pointer in cell N4 and in the shape of a block plus sign, drag the pointer down to cell N6 to select the
range (Figure 1–36).
range N4:N6
selected
Figure 1–36
3
Q&A
• Click the AutoSum button (Home tab | Editing group) to calculate the sums of all three rows (Figure 1–37).
How does Excel create unique totals for each row?
If each cell in a selected range is adjacent to a row of numbers, Excel assigns the SUM function to each cell when
you click the Sum button.
AutoSum button
SUM function entered
in range N4:N6
Figure 1–37
4
• Repeat Steps 1–3 to select cells N9 to N17 and calculate the sums of the corresponding rows (Figure 1–38).
AutoSum button
SUM function entered
in range N9:N17
Figure 1–38
Calculating Average, Maximum, and Minimum
Values
As you learned earlier in this module, the AutoSum list lets you calculate not only sums
but also the average, the number of items, or the maximum or minimum value of a range.
You can calculate these using three additional functions: AVERAGE, MAX, and MIN. The
AVERAGE function calculates the average value in a range of cells, the MAX function
calculates the maximum value in a range of cells, and the MIN function calculates the
minimum value in a range of cells. Table 1–3 shows examples of each of these functions.
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-25
EX 1-26 Excel Module 1 Creating a Worksheet and a Chart
Table 1–3 AVERAGE, MAX, and MIN Functions
Function
Result
=AVERAGE(H1:H5)
Determines the average of the values in cells H1, H2, H3, H4, and H5
=MAX(H1:H5)
Determines the maximum value entered in cells H1, H2, H3, H4, and H5
=MIN(H1:H5)
Determines the minimum value entered in cells H1, H2, H3, H4, and H5
To Enter a Formula Using the Keyboard
The net for each month, which will appear in row 19, is equal to the income total in row 6 minus the
expense total in row 17. The formula needed in the worksheet is noted in the requirements document as follows:
Net income (row 19) = Total income (row 6) – Total Expenses (row 17)
The following steps enter the net income formula in cell B19 using the keyboard. Why? Sometimes a
predefined function does not fit your needs; therefore, you enter a formula of your own.
1
• Select cell B19 to deselect the selected range.
• Type =b6-b17 in the cell. The formula is displayed in the formula bar and the current cell, and colored borders
Q&A
are drawn around the cells referenced in the formula (Figure 1–39).
What occurs on the worksheet as I enter the formula?
The equal sign (=) preceding b6–b17 in the formula alerts Excel that you are entering a formula or function and not
text. Because the most common error when entering a formula is to reference the wrong cell, Excel highlights the
cell references in the formula in color and uses the same colors to highlight the borders of the cells to help ensure
that your cell references are correct. The minus sign (–) following b6 in the formula is the arithmetic operator that
directs Excel to perform the subtraction operation.
formula displayed
in formula bar
formula entered in B19 (green
outline), which will display B6 (blue
highlight) minus B17 (red highlight)
Figure 1–39
2
• Click cell C19
to complete
the arithmetic
operation, display
the result in the
worksheet, and
select the cell to the
right (Figure 1–40).
cell C19 selected
sum displayed
Figure 1–40
To Copy a Cell to Adjacent Cells in a Row Using the Fill Handle
The easiest way to copy the SUM formula from cell B19 to cells C19, D19, E19, F19, G19, H19, I19, J19,
K19, L19, M19, and N19 is to use the fill handle. The following steps use the fill handle to copy the formula in
cell B19 to the adjacent cells C19:N19.
1
Select cell B19.
2
Drag the fill handle to select the destination area, range C19:N19, which highlights and draws a border around
the source area and the destination area. Release the mouse button to copy the function from the active cell to
the destination area and calculate the results.
Saving the Project
While you are building a worksheet in a workbook, the computer stores it in memory.
When you save a workbook, the computer places it on a storage medium such as a hard
drive, USB flash drive, or online using a service such as OneDrive. A saved workbook is
called a file. A file name is the name assigned to a file when you save it. It is important
to save the workbook frequently for the following reasons:
• The worksheet in memory will be lost if the computer is turned off or you lose
electrical power while Excel is open.
BTW
Organizing Files
and Folders
You should organize and store
files in folders so that you can
easily find the files later. For
example, if you are taking
an introductory technology
class called CIS 101, a good
practice would be to save all
Excel files in an Excel folder in
a CIS 101 folder.
Where should you save the workbook?
When saving a workbook, you must decide which storage medium to use:
• If you always work on the same computer and have no need to transport your projects to a different location, then your
computer’s hard drive will suffice as a storage location. It is a good idea, however, to save a backup copy of your projects
on a separate medium, such as an external drive, in case the file becomes corrupted or the computer’s hard drive fails. The
workbooks used in this book are saved to the computer’s hard drive.
• If you plan to work on your workbooks in various locations or on multiple computers or mobile devices, then you should save
your workbooks on a portable medium, such as a USB flash drive. Alternatively, you can save your workbooks to an online
cloud storage service such as OneDrive.
CONSIDER THIS
• If you run out of time before completing your workbook, you may finish your
worksheet at a future time without starting over.
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-27
EX 1-28 Excel Module 1 Creating a Worksheet and a Chart
To Save a Workbook
The following steps save a workbook in the Documents library on the hard drive using the file name,
Frangold Real Estate Budget. Why? You have performed many tasks while creating this project and do not want to risk
losing the work completed thus far.
1
• Click File on the ribbon to open Backstage view (Figure 1–41).
Back button
Info screen
Backstage
view
Info tab selected
Figure 1–41
2
• Click Save As in
Backstage view to
display the Save As
screen (Figure 1–42).
Save As screen
recent save
locations
Save As
available save
locations
Figure 1–42
3
• Click This PC in the
Other locations
section to display
the default save
location on the
computer or mobile
device (Figure 1–43).
More options link
This PC selected
Figure 1–43
4
New folder button
• Click the More options link to
display the Save As dialog box.
• If necessary, click Documents in
Save As dialog box
file will be saved in
Documents library
the Navigation pane to select the
Documents library as the save
location.
• Type Frangold Real
Q&A
Estate Budget in the File
name text box to specify the
file name for the workbook
(Figure 1–44).
Do I have to save to the
Documents library?
No. You can save to any device
or folder. A folder is a specific
location on a storage medium.
You can save to the default folder
or a different folder. You also
can create your own folders by
clicking the New folder button
shown in Figure 1–44. To save to
a different location, navigate to
that location in the Navigation pane instead of clicking Documents.
file name entered in
File name text box
Save button
Figure 1–44
What characters can I use in a file name?
The only invalid characters are the backslash (\), slash (/), colon (:), asterisk (*), question mark (?), quotation mark
(“), less than symbol (<), greater than symbol (>), and vertical bar (|).
Why is my list of files, folders, and drives arranged and named differently from those shown in the figure?
Your computer or mobile device’s configuration determines how the list of files and folders is displayed and how
drives are named. You can change the save location by clicking links in the Navigation pane.
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-29
EX 1-30 Excel Module 1 Creating a Worksheet and a Chart
5
• Click the Save button to save the workbook with the file name Frangold Real Estate Budget to the default save
Q&A
location (Figure 1–45).
How do I know that Excel saved the workbook?
While Excel is saving your file, it briefly displays a message on the status bar indicating the amount of the file saved.
When the workbook appears after saving, the new file name and the word, Saved, appear in the title bar.
Why is the AutoSave button disabled on the title bar?
If you are saving the file to a computer or mobile device, the AutoSave button on the title bar may be disabled
(dimmed). If you are saving the file to OneDrive, the AutoSave button may be enabled, allowing you to specify
whether Excel saves the workbook as you make changes to it. If AutoSave is turned off, you will need to continue
saving your changes manually.
new file name
appears in title bar
results of formula display
in row 19
Figure 1–45
Other Ways
1. Press F12, type file name (Save As dialog box), navigated to desired save location, click Save button
Break Point: If you want to take a break, this is a good place to do so. You can exit Excel now. To resume later, start
Excel, open the file called Frangold Real Estate Budget, and continue following the steps from this location forward.
Formatting the Worksheet
The text, numeric entries, and functions for the worksheet now are complete. The next
step is to format the worksheet. You format a worksheet to enhance the appearance of
information by changing its font, size, color, or alignment.
Figure 1–46a shows the worksheet before formatting. Figure 1–46b shows the
worksheet after formatting. As you can see from the two figures, a worksheet that is
formatted not only is easier to read but also looks more professional.
• Identify in what ways you want to emphasize various elements of the worksheet.
• Increase the font size of cells.
• Change the font color of cells.
• Center the worksheet titles, subtitles, and column headings.
• Modify column widths to best fit text in cells.
• Change the font style of cells.
(a) Unformatted Worksheet
(b) Formatted Worksheet
Figure 1–46
Excel Module 1
What steps should you consider when formatting a worksheet?
The key to formatting a worksheet is to consider the ways you can enhance the worksheet so that it appears professional.
When formatting a worksheet, consider the following steps:
CONSIDER THIS
Creating a Worksheet and a Chart Excel Module 1 EX 1-31
EX 1-32 Excel Module 1 Creating a Worksheet and a Chart
To change the unformatted worksheet in Figure 1–46a so that it looks like the
formatted worksheet in Figure 1–46b, the following tasks must be completed:
1. Change the font, change the font style, increase the font size, and change the
font color of the worksheet titles in cells A1 and A2.
2. Center the worksheet titles in cells A1 and A2 across columns A through N.
3. Format the body of the worksheet. The body of the worksheet, range A3:N19,
includes the column titles, row titles, and numbers. Formatting the body of the
worksheet changes the numbers to use a dollars-and-cents format, with dollar
signs in rows 4 and 9 and in the total rows (row 6 and 17); changes the styles
of some rows; adds underlining that emphasizes portions of the worksheet; and
modifies the column widths to fit the text in the columns and make the text and
numbers readable.
Although the formatting procedures are explained in the order described above,
you could make these format changes in any order. Modifying the column widths,
however, is usually done last because other formatting changes may affect the size of
data in the cells in the column.
Font Style, Size, and Color
The characters that Excel displays on the screen are a specific font, style,
size, and color. The font defines the appearance and shape of the letters, numbers,
and special characters. Examples of fonts include Calibri, Cambria, Times New
Roman, Arial, and Courier. A font style is a format that indicates how characters
are emphasized, such as bold, underline, and italic. The font size refers to the size
of characters, measured in units called points. A point is a unit of measure used for
font size and, in Excel, row height; one point is equal to 1/72 of an inch. Thus, a
character with a point size of 10 is 10/72 of an inch in height. Finally, Excel has
a wide variety of font colors. Font color refers to the color of the characters in a
spreadsheet.
When Excel first starts, the default font for the entire workbook is Calibri, with
a font size, font style, and font color of 11-point regular black. You can change the
font characteristics in a single cell, a range of cells, the entire worksheet, or the entire
workbook.
To Change a Cell Style
You can change several characteristics of a cell, such as the font, font size, and font color, all at once by
assigning a predefined cell style to a cell. A cell style is a predesigned combination of font, font size, and font
color that you can apply to a cell. Why? Using the predesigned styles provides a consistent appearance to common
portions of your worksheets, such as worksheet titles, worksheet subtitles, column headings, and total rows. The following
steps assign the Title cell style to the worksheet title in cell A1.
1
• Click cell A1 to make cell A1 the active cell.
• Click the Cell Styles button (Home tab | Styles group) to display the Cell Styles gallery (Figure 1–47).
Cell Styles
button
cell A1
selected
Cell Styles
gallery
Figure 1–47
2
• Point to the Title cell style in the Titles and Headings area of the Cell Styles gallery to see a live preview of the cell
style in the active cell (Figure 1–48).
Experiment
• If you are using a mouse, point to other cell styles in the Cell Styles gallery to see a live preview of those cell styles
in cell A1.
Title and
Headings area
live preview of Title
cell style in cell A1
Figure 1–48
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-33
EX 1-34 Excel Module 1 Creating a Worksheet and a Chart
3
• Click the Title cell
Q&A
style to apply the cell
style to the active
cell (Figure 1–49).
Why do settings in
the Font group on
the ribbon change?
The font and font
size change to
reflect the font
changes applied to
the active cell, cell
A1, as a result of
applying the Title
cell style.
cell A1 formatted
using Title cell style
Figure 1–49
To Change the Font
Why? Different fonts are often used in a worksheet to make it more appealing to the reader and to relate or
distinguish data in the worksheet. The following steps change the worksheet subtitle’s font to Arial Narrow.
1
• Click cell A2 to make
Font arrow
it the active cell.
• Click the Font arrow
(Home tab | Font
group) to display
the Font gallery. If
necessary, scroll to
Arial Narrow.
• Point to Arial
Narrow in the Font
gallery to see a
live preview of the
selected font in the
active cell (Figure
1–50).
Experiment
• If you are using a
mouse, point to
several other fonts
in the Font gallery
to see a live preview
of the other fonts in
the selected cell.
Font gallery
live preview of
Arial Narrow
font in cell A2
Arial Narrow
font
Figure 1–50
2
• Click Arial Narrow
in the Font
gallery to change
the font of the
worksheet subtitle
to Arial Narrow
(Figure 1–51).
Arial Narrow
font applied
to cell A2
Figure 1–51
Other Ways
1. Click Font Settings Dialog Box Launcher,
click Font tab (Format Cells dialog box),
click desired color in Color list,
click OK
2. Right-click the cell to display Mini
toolbar, click Font Color arrow on Mini
toolbar, click desired font color in Font
Color gallery
3. Right-click selected cell, click Format Cells on
shortcut menu, click Font tab (Format Cells
dialog box), click desired color in Color list,
click OK
To Apply Bold Style to a Cell
Bold, or boldface, text has a darker appearance than normal text. Why? You apply bold style to a cell
to emphasize it or make it stand out from the rest of the worksheet. The following steps apply bold style to the
worksheet title and subtitle.
1
• Click cell A1 to make it active and then click
Q&A
the Bold button (Home tab | Font group) to
change the font style of the active cell to bold
(Figure 1–52).
Bold button
What if a cell already has the bold style
applied?
If the active cell contains bold text, then Excel
displays the Bold button with a darker gray
background.
How do I remove the bold style from a cell?
Clicking the Bold button (Home tab | Font
group) a second time removes the bold style.
2
• Repeat Step 1 to bold cell A2.
bold applied
to cell A1
Figure 1–52
Other Ways
1. Click Font Settings Dialog Box Launcher, click Font tab (Format Cells
dialog box), click Bold in Font style list, click OK
3. Right-click selected cell, click Format Cells on shortcut menu, click Font
tab (Format Cells dialog box), click Bold in Font style list, click OK
2. Right-click selected cell, click Bold button on Mini toolbar
4. Press CTRL+B
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EX 1-36 Excel Module 1 Creating a Worksheet and a Chart
To Increase the Font Size of a Cell Entry
Increasing the font size is the next step in formatting the worksheet subtitle. Why? You increase the font size
of a cell so that the entry stands out and is easier to read. The following steps increase the font size of the worksheet
subtitle in cell A2.
1
Font Size arrow
• With cell A2 selected, click the
Font Size arrow (Home tab |
Font group) to display the Font
Size gallery.
• Point to 16 in the Font Size
gallery to see a live preview of
the active cell with the selected
font size (Figure 1–53).
Font Size gallery
Experiment
• If you are using a mouse, point
to several other font sizes in
the Font Size list to see a live
preview of those font sizes in
the selected cell.
font size 16
bold applied to
cell A2
Figure 1–53
2
• Click 16 in the Font Size gallery
Q&A
to change the font size in the
active cell (Figure 1–54).
Can I choose a font size that is
not in the Font Size gallery?
Yes. To select a font size not
displayed in the Font Size
gallery, such as 13, click the
Font Size box (Home tab | Font
group), type the font size you
want, and then press ENTER.
font size
changed
Figure 1–54
Other Ways
1. Click ‘Increase Font Size’ button
(Home tab | Font group) or
‘Decrease Font Size’ button
(Home tab | Font group)
2. Click Font Settings Dialog Box
Launcher, click Font tab (Format
Cells dialog box), click desired
size in Size list, click OK
3. Right-click cell to display Mini
toolbar, click Font Size arrow
on Mini toolbar, click desired
font size in Font Size gallery
4. Right-click selected cell, click Format
Cells on shortcut menu, click Font
tab (Format Cells dialog box), select
font size in Size box, click OK
To Change the Font Color of a Cell Entry
The next step is to change the color of the font in cells A1 and A2 to green. Why? Changing the font color
of cell entries can help the text stand out more. You also can change the font colors to match a company’s or product’s brand
colors. The following steps change the font color of a cell entry.
1
• Click cell A1 and then click the
Font Color arrow (Home tab | Font
group) to display the Font Color
gallery.
Font Color arrow
• If you are using a mouse, point
to Green, Accent 6 (column 10,
row 1) in the Theme Colors area
of the Font Color gallery to see a
live preview of the font color in
the active cell (Figure 1–55).
Font Color
gallery
live preview
of color
Experiment
‘Green,
Accent 6’
• Point to several other colors in
Q&A
the Font Color gallery to see a live
preview of other font colors in the
active cell.
How many colors are in the Font
Color gallery?
Figure 1–55
You can choose from
approximately 70 different font colors in the Font Color gallery. Your Font Color gallery may have more or fewer
colors, depending on the color settings of your operating system. The Theme Colors area contains colors that are
included in the current workbook’s theme.
2
• Click Green, Accent 6 (column 10, row 1) in the Font Color gallery to
Q&A
change the font color of the worksheet title in the active cell (Figure 1–56).
Why does the Font Color button change after I select the new font color?
When you choose a color on the Font Color gallery, Excel changes the Font
Color button (Home tab | Font group) to your chosen color. Then when you
want to change the font color of another cell to the same color, you need
only to select the cell and then click the Font Color button (Home tab |
Font group).
font color
changed
3
Figure 1–56
• Click cell A2.
• Click the Font Color button to apply Green, Accent 6 (column 10, row 1)
to cell A2.
Other Ways
1. Click Font Settings Dialog Box Launcher,
click Font tab (Format Cells dialog box),
click desired font color in Color list, click OK
2. Right-click cell to display Mini toolbar,
click Font Color arrow on Mini toolbar,
click desired color in Font Color gallery
3. Right-click selected cell, click Format Cells on
shortcut menu, click Font tab (Format Cells dialog
box), click Color arrow, click desired color, click OK
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EX 1-38 Excel Module 1 Creating a Worksheet and a Chart
To Center Cell Entries across Columns by Merging Cells
The final step in formatting the worksheet title and subtitle is to center them across columns A through N.
Why? Centering a title across the columns used in the body of the worksheet improves the worksheet’s appearance. To do this,
the 14 cells in the range A1:N1 are combined, or merged, into a single cell that is the width of the columns in the
body of the worksheet. The 14 cells in the range A2:N2 are merged in a similar manner. When you merge cells,
you combine multiple adjacent cells into one larger cell. To unmerge cells, you split them to display the original
range of cells. The following steps center the worksheet title and subtitle across columns by merging cells.
1
Q&A
• Select cell A1 and then drag to cell N1 to highlight the range to be merged and centered (Figure 1–57).
What if a cell in the range B1:N1 contains data?
For the ‘Merge & Center’ button (Home tab | Alignment group) to work properly, all the cells except the leftmost cell in
the selected range must be empty.
range A1:N1
selected for
merging
Figure 1–57
2
• Click the ‘Merge & Center’ button (Home tab | Alignment group) to merge cells A1 through N1 and center the
Q&A
contents of the leftmost cell across the selected columns (Figure 1–58).
What if my screen displays a Merge & Center menu?
If you are using a touch screen, Excel might display a Merge & Center menu. Select the desired option on the Merge
& Center menu if you do not have a separate ‘Merge & Center’ button and ‘Merge & Center’ arrow.
What happened to cells B1 through N1?
After the merge, cells B1 through N1 no longer exist. The new cell A1 now extends across columns A through N.
‘Merge &
Center’ button
cell range merged and text
centered in one cell (A1)
Figure 1–58
3
• Repeat Steps 1 and 2
Q&A
to merge and center
the worksheet
subtitle across cells
A2 through N2
(Figure 1–59).
cells merged and
centered
Are cells B1 through
N1 and B2 through
N2 lost forever?
No. You can split
a merged cell to
Figure 1–59
redisplay the individual
cells. You split a merged cell by selecting it and clicking the ‘Merge & Center’ button. For example, if you click the
‘Merge & Center’ button a second time in Step 2, it will split the merged cell A1 into cells A1, B1, C1, D1, E1, F1, G1,
H1, I1, J1, K1, L1, M1, and N1, and move the title to its original location in cell A1.
Other Ways
1. Right-click selection, click ‘Merge & Center’
button on Mini toolbar
2. Right-click selected cell, click Format Cells on shortcut menu, click Alignment tab (Format
Cells dialog box), select ‘Center Across Selection’ in Horizontal list, click OK
To Format Rows Using Cell Styles
The next step to format the worksheet is to format the rows. Why? Row titles and the total row should be
formatted so that the column titles and total row can be distinguished from the data in the body of the worksheet. Data
rows can be formatted to make them easier to read as well. The following steps format the column titles and total row
using cell styles in the default worksheet theme.
1
• Click cell A3 and then drag to cell N3 to select the range.
• Click the Cell Styles button (Home tab | Styles group) to display the Cell Styles gallery.
• Point to the Heading 1 cell style in the Titles and Headings area of the Cell Styles gallery to see a live preview of the
cell style in the selected range (Figure 1–60).
Experiment
• If you are using a mouse, point to other cell styles in the Titles and Headings area of the Cell Styles gallery to see a
live preview of other styles.
Cell Styles
button
Cell Styles
gallery
live preview
of cell style
Heading 1 cell style
Figure 1–60
Excel Module 1
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EX 1-40 Excel Module 1 Creating a Worksheet and a Chart
2
• Click the Heading 1
Center
button
cell style to apply
the cell style to the
selected range.
• Click the Center
button (Home tab |
Alignment group) to
center the column
headings in the
selected range.
Heading 1 style
applied and column
heading centered
• Select the range A8
to N8 (Figure 1–61).
3
range
A8:N8
Figure 1–61
• Apply the Heading 1
cell style format
and then center the
headings (Figure
1–62).
Heading 1 style
applied and
column headings
centered
4
Figure 1–62
• Format the ranges
A6:N6 and A17:N17
with the Total cell
style format.
• Format the range
A19:N19 with the
Accent6 cell style
format.
• Format the ranges
A4:N4, A9:N9,
A11:N11, A13:N13,
A15:N15 with the
20% - Accent6 cell
style format.
styles
applied to
all rows
• Format the range
A5:N5, A10:N10,
A12:N12, A14:N14,
A16:N16 with the
40% - Accent6
cell style format.
Deselect the selected
ranges (Figure 1–63).
Figure 1–63
To Format Numbers in the Worksheet
The requirements document requested that numbers in the first row and last row of each section should
be formatted to use a dollar-and-cents format, while other numbers receive a comma format. Why? Using a
dollar-and-cents format for selected cells makes it clear to users of the worksheet that the numbers represent dollar values
without cluttering the entire worksheet with dollar signs, and applying the comma format makes larger numbers easier
to read. Excel allows you to apply various number formats, many of which are discussed in later modules. The
following steps use buttons on the ribbon to format the numbers in the worksheet.
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-41
1
• Select the range
B4:N4.
• Click the
‘Accounting Number
Format’ button
(Home tab | Number
group) to apply the
accounting number
format to the cells
in the selected
range.
‘Accounting Number
Format’ button
accounting number
format applied to
range B4:N4
range B5:N5 selected
• Select the range
Q&A
B5:N5 (Figure 1–64).
Figure 1–64
What if my screen displays an Accounting Number Format menu?
If you are using a touch screen, you may not have a separate ‘Accounting Number Format’ button and ‘Accounting
Number Format’ arrow. In this case, select the desired option on the Accounting Number Format menu.
What effect does the accounting number format have on the selected cells?
The accounting number format causes numbers to be displayed with two decimal places and to align vertically.
Cell widths are adjusted automatically to accommodate the new formatting.
2
Q&A
• Click the Comma Style button (Home tab | Number group) to apply the comma style format to the selected range.
What effect does the comma style format have on the selected cells?
The comma style format formats numbers to have two decimal places and commas as thousands separators.
• Select the range B6:N6 to make it the active range (Figure 1–65).
Comma Style button
comma style format
applied to range B5:N5
Figure 1–65
range B6:N6 selected
EX 1-42 Excel Module 1 Creating a Worksheet and a Chart
3
• Click the ‘Accounting Number Format’ button (Home tab | Number group) to apply the accounting number format
to the cells in the selected range.
4
• Format the ranges B9:N9, B17:N17, and B19:N19 with the accounting number format.
Q&A
• Format the range B10:N16 with the comma style format. Click cell A1 to deselect the selected ranges (Figure 1–66).
How do I select the range B10:N16?
Select this range the same way as you select a range of cells in a column or row; that is, click the first cell in the
range (B10, in this case) and drag to the last cell in the range (N16, in this case).
accounting number
format applied
formats applied to
remaining rows
Figure 1–66
Other Ways
1. Click ‘Accounting Number Format’ or
Comma Style button on Mini toolbar
2. Right-click selected cell, click Format Cells on shortcut menu, click Number tab (Format Cells dialog
box), select Accounting in Category list or select Number and click ‘Use 1000 Separator’, click OK
To Adjust the Column Width
The last step in formatting the worksheet is to adjust the width of the columns so that each title is visible.
Why? To make a worksheet easy to read, the column widths should be adjusted appropriately. Excel offers other methods
for adjusting cell widths and row heights, which are discussed later in this book. The following steps adjust the
width of columns A through N so that the contents of the columns are visible.
1
• Point to the
boundary on the
right side of the
column A heading
above row 1 to
change the pointer
to a split double
arrow (Figure 1–67).
pointer changes to
split double arrow
Figure 1–67
2
• Double-click the boundary to
Q&A
adjust the width of the column
to accommodate the width of
the longest item in the column
(Figure 1–68).
What if all of the items in the
column are already visible?
If all of the items are shorter in
length than the width of the
column and you double-click the
column boundary, Excel will reduce
the width of the column to the
width of the widest entry.
column A resized
cell contents visible
Figure 1–68
3
• Repeat Steps 1 and 2 to adjust the column width of columns B through N (Figure 1–69).
columns B through
N resized
Figure 1–69
Other Ways
1. Select column heading, click Format (Home tab | Cells group), click AutoFit Column Width
Excel Module 1
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EX 1-44 Excel Module 1 Creating a Worksheet and a Chart
To Use the Name Box to Select a Cell
The next step is to chart the monthly expenses. To create the chart, you need to identify the range of the
data you want to feature on the chart and then select it. In this case you want to start with cell A3. Rather than
clicking cell A3 to select it, you will select the cell by using the Name box, which is located to the left of the
formula bar. Why? You might want to use the Name box to select a cell if you are working with a large worksheet and
it is faster to type the cell name rather than scrolling to and clicking it. The following steps select cell A3 using the
Name box.
1
• Click the Name
box in the formula
bar and then type
a3 as the cell
you want to select
(Figure 1–70).
a3 entered
in Name box
Figure 1–70
2
• Press ENTER to
change the active
cell in the Name
box and make cell
A3 the active cell
(Figure 1–71).
cell A3 is active cell
Figure 1–71
Other Ways to Select Cells
As you will see in later modules, in addition to using the Name box to select any
cell in a worksheet, you also can use it to assign names to a cell or range of cells. Excel
supports several additional ways to select a cell, as summarized in Table 1–4.
Table 1–4 Selecting Cells in Excel
Key, Box, or Command
Function
alt+page down
Selects the cell one worksheet window to the right and moves the worksheet window accordingly.
alt+page up
Selects the cell one worksheet window to the left and moves the worksheet window accordingly.
arrow
Selects the adjacent cell in the direction of the arrow on the key.
ctrl+arrow
Selects the border cell of the worksheet in combination with the arrow keys and moves the worksheet window
accordingly. For example, to select the rightmost cell in the row that contains the active cell, press ctrl+right
arrow. You also can press end, release it, and then press the appropriate arrow key to accomplish the same
task.
ctrl+home
Selects cell A1 or the cell one column and one row below and to the right of frozen titles and moves the
worksheet window accordingly.
Find command on Find &
Select menu (Home tab |
Editing group) or shift+f5
Finds and selects a cell that contains specific contents that you enter in the Find and Replace dialog box. If
necessary, Excel moves the worksheet window to display the cell. You also can press ctrl+f to display the Find
and Replace dialog box.
Go To command on Find
& Select menu (Home tab |
Editing group) or f5
Selects the cell that corresponds to the cell reference you enter in the Go To dialog box and moves the
worksheet window accordingly. You also can press ctrl+g to display the Go To dialog box and its Special
button to go to special worksheet elements, such as formulas.
home
Selects the cell at the beginning of the row that contains the active cell and moves the worksheet window
accordingly.
Name box
Selects the cell in the workbook that corresponds to the cell reference you enter in the Name box.
page down
Selects the cell down one worksheet window from the active cell and moves the worksheet window
accordingly.
page up
Selects the cell up one worksheet window from the active cell and moves the worksheet window accordingly.
Break Point: If you want to take a break, this is a good place to do so. Be sure to save the Frangold Real Estate
Budget file again, and then you can exit Excel. To resume later start Excel, open the file called Frangold Real Estate
Budget, and continue following the steps from this location forward.
Adding a Pie Chart to the Worksheet
Excel includes 17 chart types from which you can choose, including column, line, pie,
bar, area, X Y (scatter), map, stock, surface, radar, treemap, sunburst, histogram, box &
whisker, waterfall, funnel, and combo. The type of chart you choose depends on the
type and quantity of data you have and the message or analysis you want to convey.
A column chart is a good way to compare values side by side. A line chart is
often used to illustrate changes in data over time. Pie charts show the contribution of
each piece of data to the whole, or total, of the data. A pie chart can go even further
in comparing values across categories by showing each pie piece in comparison with
the others. Area charts, like line charts, illustrate changes over time but are often used
to compare more than one set of data, and the area below the lines is filled in with a
different color for each set of data. An X Y (scatter) chart is used much like a line chart,
but each piece of data is represented by a dot and is not connected with a line. Scatter
charts are typically used for viewing scientific, statistical, and engineering data. A map
chart depicts data based on geographic location. A stock chart provides a number
of methods commonly used in the financial industry to show fluctuations in stock
market data. A surface chart compares data from three columns and/or rows in a 3-D
manner. A radar chart can compare aggregate values of several sets of data in a manner
that resembles a radar screen, with each set of data represented by a different color.
A funnel chart illustrates values during various stages. A combo chart allows you to
combine multiple types of charts.
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-45
EX 1-46 Excel Module 1 Creating a Worksheet and a Chart
As outlined in the requirements document in Figure 1–2, the budget worksheet
should include a pie chart to graphically represent the yearly expense totals for each
item in Frangold Real Estate’s budget. The pie chart shown in Figure 1–72 is on its
own sheet in the workbook. The pie chart resides on a separate sheet, called a chart
sheet. A chart sheet is a separate sheet in a workbook that contains only a chart, which
is linked to the workbook data.
chart title
pie chart
chart legend
chart sheet
Figure 1–72
In this worksheet, the ranges you want to chart are the nonadjacent ranges
A9:A16 (expense titles) and N9:N16 (yearly expense totals). The expense titles in the
range A9:A16 will identify the slices of the pie chart; these entries are called category
names. The range N9:N16 contains the data that determine the size of the slices in
the pie; these entries are called the data series. A data series is a column or row in a
datasheet and also the set of values represented in a chart. Because eight budget items
are being charted, the pie chart contains eight slices.
To Add a Pie Chart
Why? When you want to see how each part relates to the whole, you use a pie chart. The following steps draw the
pie chart.
1
• Select the range A9:A16 to identify the range of the category names for the pie chart.
• While holding down CTRL, select the nonadjacent range N9:N16.
• Click Insert on the ribbon to display the Insert tab.
• Click the ‘Insert Pie or Doughnut Chart’ button (Insert tab | Charts group) to display the Insert Pie or Doughnut
Chart gallery (Figure 1–73).
Insert tab
‘Insert Pie or
Doughnut
Chart’ button
Pie
‘Insert Pie or
Doughnut
Chart’ gallery
ranges A9:A16
and N9:N16
selected
Figure 1–73
2
• Click Pie in the 2-D
Q&A
category of the Insert
Pie or Doughnut
Chart gallery to
insert the chart
in the worksheet
(Figure 1–74).
Why have new tabs
appeared on the
ribbon?
The new tabs
provide additional
options and
functionality when
you are working
with certain objects,
such as charts, and
only display when
you are working
with those objects.
pie chart
created
Figure 1–74
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-47
EX 1-48 Excel Module 1 Creating a Worksheet and a Chart
3
• Click the chart title
to select it.
• Click and drag to
chart title
select all the text in
the chart title.
• Type Monthly
Expenses to
specify the title.
• Click a blank area of
the chart to deselect
the chart title
(Figure 1–75).
Figure 1–75
To Apply a Style to a Chart
Why? If you want to enhance the appearance of a chart, you can apply a chart style. The following steps apply
Style 6 to the pie chart.
1
• Click the Chart Styles button to the right of the chart to display the Chart Styles gallery.
• Scroll in the Chart Styles gallery to display the Style 6 chart style (Figure 1–76).
Chart Styles button
Chart Styles
gallery
scroll box
Chart Style 6
Figure 1–76
2
• Click Style 6 in the
Chart Styles gallery
to change the chart
style to Style 6
(Figure 1–77).
3
• Click the Chart Styles
button to close the
Chart Styles gallery.
Style 6
selected
Figure 1– 77
Changing the Sheet Tab Names and Colors
The sheet tabs at the bottom of the window allow you to navigate between any
worksheet in the workbook. You click the sheet tab of the worksheet you want to view
in the Excel window. By default, the worksheets are named Sheet1, Sheet2, and so
on. The worksheet names become increasingly important as you move toward more
sophisticated workbooks, especially workbooks in which you place objects such as
charts on different sheets, which you will do in the next section, or you reference cells
between worksheets.
BTW
Exploding a Pie
Chart
If you want to draw attention
to a particular slice in a pie
chart, you can offset the slice
so that it stands out from the
rest. A pie chart with one or
more slices offset is referred
to as an exploded pie chart.
To offset a slice, click the slice
two times to select it (do not
double-click) and then drag
the slice outward.
To Move a Chart to a New Sheet
Why? By moving a chart to its own sheet, the size of the chart will increase, which can improve readability. The
following steps move the pie chart to a chart sheet named Monthly Expenses.
1
Move Chart
dialog box
• Click the Move Chart button
(Chart Tools Design tab | Location
group) to display the Move Chart
dialog box (Figure 1–78).
Move Chart
button
New sheet
text box
OK button
Figure 1–78
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-49
EX 1-50 Excel Module 1 Creating a Worksheet and a Chart
2
• Click New sheet to select it (Move Chart dialog box) and then type Monthly Expense Chart in the
New sheet text box to enter a sheet tab name for the worksheet that will contain the chart.
• Click OK (Move Chart dialog box) to move the chart to a new chart sheet with the sheet tab name, Monthly
Expense Chart (Figure 1–79).
chart moved to
Monthly Expense
Chart sheet
Sheet1 tab
Figure 1–79
To Change the Sheet Tab Name and Color
You decide to change the name and color of the Sheet1 tab to Monthly Finances. Why? Use simple,
meaningful names for each sheet tab. Sheet tab names often match the worksheet title. If a worksheet includes multiple
titles in multiple sections of the worksheet, use a sheet tab name that encompasses the meaning of all of the sections.
Changing the tab color also can help uniquely identify a sheet. The following steps rename the sheet tab and
change the tab color.
1
• Double-click the sheet tab labeled Sheet1 in the
lower-left corner of the window.
• Type Monthly Finances as the sheet tab
Q&A
name and then press ENTER to assign the new
name to the sheet tab (Figure 1–80).
sheet tab name
changed
What is the maximum length for a sheet tab
name?
Sheet tab names can be up to 31 characters
Figure 1–80
(including spaces) in length. Longer worksheet
names, however, mean that fewer sheet tabs will appear on your screen. If you have multiple worksheets with long
sheet tab names, you may have to scroll through sheet tabs, making it more difficult to find a particular sheet.
2
shortcut menu
• Right-click the sheet tab labeled
Monthly Finances, in the lowerleft corner of the window, to
display a shortcut menu.
Green,
Accent 6
• Point to Tab Color on the shortcut
menu to display the Tab Color
gallery (Figure 1–81).
Tab Color
command
Tab Color
gallery
Figure 1–81
3
Home tab
• Click Green, Accent 6 (column 10,
row 1) in the Theme Colors area
to change the color of the tab
(Figure 1–82).
• If necessary, click Home on the
ribbon to display the Home tab.
• Click the Save button on the
Q&A
Quick Access Toolbar to save the
workbook again on the same
storage location with the same
file name.
Why should I save the workbook
again?
You have made several
modifications to the workbook
since you last saved it. Thus, you
should save it again.
What if I want to change the file
name or storage location when I
save the workbook?
Click Save As in Backstage
view and follow the “To Save a
Workbook” steps earlier in this
module to specify a different file
name and/or storage location.
tab color changed
to Green, Accent 6
Figure 1–82
Document Properties
Excel helps you organize and identify your files by using document properties, which
are the details about a file such as the project author, title, and subject. For example,
you could use the class name or topic to describe the workbook’s purpose or content in
the document properties.
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-51
Why would you want to assign document properties to a workbook?
Document properties are valuable for a variety of reasons:
• Users can save time locating a particular file because they can view a file’s document properties without opening the
workbook.
• By creating consistent properties for files having similar content, users can better organize their workbooks.
• Some organizations require Excel users to add document properties so that other employees can view details about these
files.
Common document properties include standard properties and those that are
automatically updated. Standard properties are document properties associated with
all Microsoft Office files and include author, title, and subject. Automatically updated
properties are file system or document properties, such as the date you create or
change a file, and statistics, such as the file size.
TO CHANGE DOCUMENT PROPERTIES
To change document properties, you would follow these steps.
1. Click File on the ribbon to open Backstage view and then, if necessary, click
the Info tab in Backstage view to display the Info screen. The Properties list is
located in the right pane of the Info screen.
2. If the property you want to change is in the Properties list, click to the right
of the property category to display a text box. (Note that not all properties are
editable.) Type the desired text for the property and then click anywhere in the
Info screen to enter the data or press TAB to navigate to the next property. Click
the Back button in the upper-left corner of Backstage view to return to the Excel
window.
3. If the property you want to change is not in the Properties list or you cannot
edit it, click the Properties button to display the Properties menu, and then
click Advanced Properties to display the Summary tab in the Properties dialog
box. Type your desired text in the appropriate property text boxes. Click OK
(Properties dialog box) to close the dialog box and then click the Back button in
the upper-left corner of Backstage view to return to the workbook.
Q&A
CONSIDER THIS
EX 1-52 Excel Module 1 Creating a Worksheet and a Chart
Why do some of the document properties in my Properties dialog box contain data?
Depending on where you are using Excel, your school, university, or place of
employment may have customized the properties.
Printing a Worksheet
After creating a worksheet, you may want to preview and print it. A preview is an
onscreen view of your document prior to printing, to see exactly how the printed
document will look. Printing a worksheet enables you to distribute the worksheet
to others in a form that can be read or viewed but not edited. It is a good practice to
save a workbook before printing a worksheet, in the event you experience difficulties
printing.
• Some people prefer proofreading a hard copy of a workbook rather than viewing it on the screen to check for errors and
readability.
• Hard copies can serve as a backup reference if your storage medium is lost or becomes corrupted and you need to recreate
the workbook.
Instead of distributing a hard copy of a workbook, users can distribute the workbook as an electronic image that mirrors the
original workbook’s appearance. An electronic image of a workbook is not an editable file; it simply displays a picture of the
workbook. The electronic image of the workbook can be sent as an email attachment, posted on a website, or copied to a
portable storage medium such as a USB flash drive. Two popular electronic image formats, sometimes called fixed formats, are
PDF by Adobe Systems and XPS by Microsoft. In Excel, you can create electronic image files through the Save As dialog box and
the Export, Share, and Print tabs in Backstage view. Electronic images of workbooks, such as PDF and XPS, can be useful for the
following reasons:
• Users can view electronic images of workbooks without the software that created the original workbook (e.g., Excel). Specifically, to view a PDF file, you use a program called Adobe Reader, which can be downloaded free from the Adobe website.
Similarly, to view an XPS file, you use a program called XPS Viewer, which is included in the latest version of Windows.
• Sending electronic workbooks saves paper and printer supplies. Society encourages users to contribute to green computing, which involves reducing the electricity consumed and environmental waste generated when using computers, mobile
devices, and related technologies.
To Preview and Print a Worksheet in Landscape Orientation
With the completed workbook saved, you may want to print it. Why? A printed copy is sometimes necessary for
a report delivered in person.
An on-screen preview of your worksheet lets you see each page of your worksheet in the current
orientation. Portrait orientation describes a printed copy with the short (8½") edge at the top of the printout;
the printed page is taller than it is wide. Landscape orientation describes the page orientation in which the
page is wider than it is tall. The print settings allow you to change the orientation as well as the paper size,
margins, and scaling. Scaling determines how the worksheet fits on the page. You may want to adjust scaling to
ensure that your data fits on one sheet of paper. Why? A printed worksheet may be difficult to read if it is spread across
more than one page. The following steps print one or more hard copies of the contents of the worksheet.
1
• Click File on the ribbon to open Backstage view.
Q&A
• Click Print in Backstage view to display the Print screen (Figure 1–83).
How can I print multiple copies of my worksheet?
Increase the number in the Copies box on the Print screen.
What if I decide not to print the worksheet at this time?
Click the Back button in the upper-left corner of Backstage view to return to the workbook window.
Why does my Print screen look different?
Depending on the type of printer you select, your Print screen may display different options.
Excel Module 1
What is the best method for distributing a workbook?
The traditional method of distributing a workbook uses a printer to produce a hard copy. A hard copy or printout is information that exists on paper. Hard copies can be useful for the following reasons:
CONSIDER THIS
Creating a Worksheet and a Chart Excel Module 1 EX 1-53
EX 1-54 Excel Module 1 Creating a Worksheet and a Chart
Print screen presents several
print options and shows a
preview of how workbook
will print
Worksheet
preview
Copies box
Printer Status
button
Print tab
options in your Settings area
may differ, depending on type
of printer you are using
specify pages to print
Portrait Orientation
button
click to select paper size
No Scaling
button
Next Page button
scrolls preview
forward to next page
Previous Page button
scrolls preview backward
to previous page
Figure 1–83
2
• Verify that the printer listed on the Printer Status button is the printer you want to use. If necessary, click the
Printer Status button to display a list of available printer options and then click the desired printer to change the
currently selected printer.
• If you want to print more than one copy, use the Copies up arrow to increase the number.
• If you want to change the paper size, use the paper size arrow (which currently reads Letter 8.5" × 11") to view and
select a different one.
3
• Click the Portrait Orientation button in the Settings area and then select Landscape Orientation to change the
orientation of the page to landscape.
• Click the No Scaling button and then select ‘Fit Sheet on One Page’ to print the entire worksheet on one page
(Figure 1–84).
Print button
name of currently
selected printer — your
printer name will differ
preview of
how workbook
will look with
printed
‘Fit Sheet on
One Page’
selected
Figure 1–84
4
• Click the Print button on the Print screen to print the worksheet in landscape orientation on the currently selected
printer.
Q&A
• When the printer stops, retrieve the hard copy (Figure 1–85).
Do I have to wait until my worksheet is complete to print it?
No, you can print a document at any time while you are creating it.
Figure 1–85
Other Ways
1. Press CTRL+P to open the Print screen, press ENTER
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-55
EX 1-56 Excel Module 1 Creating a Worksheet and a Chart
Viewing Automatic Calculations
You can easily view calculations using the AutoCalculate area, an area on the Excel
status bar where you can view a total, an average, or other information about a selected
range. First, select the range of cells containing the numbers you want to check.
Next, right-click the AutoCalculate area to display the Customize Status Bar shortcut
menu (Figure 1–86). The check marks indicate that the calculations are displayed in
the status bar; more than one may be selected. The functions of the AutoCalculate
commands on the Customize Status Bar shortcut menu are described in Table 1–5.
Table 1–5 Commonly Used Status Bar Commands
Command
Function
Average
AutoCalculate area displays the average of the numbers in the selected range
Count
AutoCalculate area displays the number of nonempty cells in the selected range
Numerical Count
AutoCalculate area displays the number of cells containing numbers in the selected range
Minimum
AutoCalculate area displays the lowest value in the selected range
Maximum
AutoCalculate area displays the highest value in the selected range
Sum
AutoCalculate area displays the sum of the numbers in the selected range
To Use the AutoCalculate Area to Determine a Maximum
The following steps determine the largest monthly total in the budget. Why? Sometimes, you want a quick
analysis, which can be especially helpful when your worksheet contains a lot of data.
1
• Select the range B19:M19. Right-click the status bar to display the Customize Status Bar shortcut menu (Figure 1–86).
Customize Status
Bar shortcut menu
check mark indicates
calculation appears on
status bar
Maximum
command
status bar
Figure 1–86
2
• Click Maximum on the shortcut menu to display the Maximum value in the range B19:M19 in the AutoCalculate
area of the status bar.
• Click anywhere on the worksheet to close the shortcut menu (Figure 1–87).
maximum value
displayed in
AutoCalculate area
Figure 1–87
3
• Right-click the AutoCalculate area and then click Maximum on the shortcut menu to deselect it. The Maximum
value will no longer appear on the status bar.
• Close the shortcut menu.
Correcting Errors
You can correct data entry errors on a worksheet using one of several methods. The
method you choose will depend on the extent of the error and whether you notice it
while entering the data or after you have entered the incorrect data into the cell.
Correcting Errors while Entering Data into a Cell
If you notice an error while you are entering data into a cell, press backspace
to erase the incorrect character(s) and then enter the correct character(s). If the error
is a major one, click the Cancel box in the formula bar or press esc to erase the entire
entry and then reenter the data.
Correcting Errors after Entering Data into a Cell
If you find an error in the worksheet after entering the data, you can correct the
error in one of two ways:
1. If the entry is short, select the cell, retype the entry correctly, and then click the
Enter button or press enter. The new entry will replace the old entry.
2. If the entry in the cell is long and the errors are minor, using Edit mode may be
a better choice than retyping the cell entry. In Edit mode, a mode that lets you
perform in-cell editing, Excel displays the active cell entry in the formula bar
and a flashing insertion point in the active cell. There you can edit the contents
directly in the cell — a procedure called in-cell editing.
a. Double-click the cell containing the error to switch Excel to Edit mode
(Figure 1–88).
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-57
EX 1-58 Excel Module 1 Creating a Worksheet and a Chart
in-cell editing
Figure 1 – 88
b. Make corrections using the following in-cell editing methods.
(1) To insert new characters between two characters, place the insertion
point between the two characters and begin typing. Excel inserts the new
characters to the left of the insertion point.
(2) To delete a character in the cell, move the insertion point to the left of
the character you want to delete and then press delete, or place the
insertion point to the right of the character you want to delete and then
press backspace. You also can drag to select the character or adjacent
characters you want to delete and then press delete or ctrl+x or
click the Cut button (Home tab | Clipboard group).
(3) When you are finished editing an entry, click the Enter button or press enter.
There are two ways to enter data in Edit mode: Insert mode and Overtype
mode. Insert mode is the default Excel mode that inserts a character and moves
all characters to the right of the typed character one position to the right. You can
change to Overtype mode by pressing insert. In Overtype mode, Excel replaces, or
overtypes, the character to the right of the insertion point. The insert key toggles the
keyboard between Insert mode and Overtype mode.
While in Edit mode, you may want to move the insertion point to various points
in the cell, select portions of the data in the cell, or switch from inserting characters
to overtyping characters. Table 1–6 summarizes the more common tasks performed
during in-cell editing.
Table 1–6 Summary of In-Cell Editing Tasks
Task
Mouse Operation
Keyboard
1.
Move the insertion point to
Point to the left of the first character
the beginning of data in a cell. and click.
Press home.
2.
Move the insertion point to
the end of data in a cell.
Point to the right of the last character
and click.
Press end.
3.
Point to the appropriate position and
click the character.
Drag through adjacent characters.
5.
Move the insertion point
anywhere in a cell.
Highlight one or more
adjacent characters.
Select all data in a cell.
6.
Delete selected characters.
7.
Delete characters to the left
of the insertion point.
Press backspace.
8.
Delete characters to the right
of the insertion point.
Press delete.
9.
Toggle between Insert and
Overtype modes.
Press insert.
4.
Press right arrow or left
arrow.
Press shift+right arrow or
shift+left arrow.
Double-click the cell with the insertion point in
the cell if the data in the cell contains no spaces.
Click the Cut button (Home tab | Clipboard
Press delete.
group).
Undoing the Last Cell Entry
The Undo button on the Quick Access Toolbar (Figure 1–89) allows you to erase
recent cell entries. Thus, if you enter incorrect data in a cell and notice it immediately,
click the Undo button and Excel changes the cell entry to what it was prior to the
incorrect data entry.
Undo button
Undo list
Figure 1–89
Excel remembers the last 100 actions you have completed. Thus, you can undo
up to 100 previous actions by clicking the Undo arrow to display the Undo list and
then clicking the action to be undone (Figure 1–89). You can drag through several
actions in the Undo list to undo all of them at once. If no actions are available for
Excel to undo, then the dimmed appearance of the Undo button indicates that it is
unavailable.
The Redo button, next to the Undo button on the Quick Access Toolbar, allows
you to repeat previous actions; that is, if you accidentally undo an action, you can use
the Redo button to perform the action again.
Clearing a Cell or Range of Cells
If you enter data into the wrong cell or range of cells, you can erase, or clear,
the data using one of the first four methods listed below. The fifth method clears the
formatting from the selected cells. To clear a cell or range of cells, you would perform
the following steps:
TO CLEAR CELL ENTRIES USING THE FILL HANDLE
1. Select the cell or range of cells and then point to the fill handle so that the
pointer changes to a crosshair.
2. Drag the fill handle back into the selected cell or range until a shadow covers the
cell or cells you want to erase.
TO CLEAR CELL ENTRIES USING THE SHORTCUT MENU
1. Select the cell or range of cells to be cleared.
2. Right-click the selection.
3. Click Clear Contents on the shortcut menu.
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-59
EX 1-60 Excel Module 1 Creating a Worksheet and a Chart
TO CLEAR CELL ENTRIES USING THE DELETE KEY
1. Select the cell or range of cells to be cleared.
2. Press delete.
TO CLEAR CELL ENTRIES AND FORMATTING USING THE CLEAR BUTTON
1. Select the cell or range of cells to be cleared.
2. Click the Clear button (Home tab | Editing group).
3. Click Clear Contents on the Clear menu, or click Clear All to clear both the cell
entry and the cell formatting.
TO CLEAR FORMATTING USING THE CELL STYLES BUTTON
1. Select the cell or range of cells from which you want to remove the formatting.
2. Click the Cell Styles button (Home tab | Styles group) and then click Normal in
the Cell Styles gallery.
As you are clearing cell entries, always remember that you should never press
the SPACEBAR to clear a cell. Pressing the spacebar enters a blank character. A blank
character is interpreted by Excel as text and is different from an empty cell, even
though the cell may appear empty.
Clearing the Entire Worksheet
If the required worksheet edits are extensive or if the requirements drastically
change, you may want to clear the entire worksheet and start over. To clear the
worksheet or delete an embedded chart, you would use the following steps.
TO CLEAR THE ENTIRE WORKSHEET
1. Click the Select All button on the worksheet. The Select All button is located
above the row 1 identifier and to the left of the column A heading.
2. Click the Clear button (Home tab | Editing group) and then click Clear All on
the menu to delete both the entries and formats.
The Select All button selects the entire worksheet. To clear an unsaved
workbook, click the Close Window button on the workbook’s title bar or click the
Close button in Backstage view. Click the No button if the Microsoft Excel dialog box
asks if you want to save changes. To start a new, blank workbook, click the New button
in Backstage view.
Using Excel Help
Once an Office app’s Help window is open, you can use several methods to
navigate Help. You can search for help by using the Help pane or the Tell me box.
To Obtain Help Using the Search Text Box
Assume for the following example that you want to know more about functions. The following steps use
the Search text box to obtain useful information about functions by entering the word, functions, as search text.
Why? You may not know the exact help topic you are looking to find, so using keywords can help narrow your search.
1
• Click Help on the ribbon to display the Help tab (Figure 1–90).
Help tab
available commands to
obtain help
Figure 1–90
2
• Click the Help button (Help group) to display the Help pane (Figure 1–91).
Help button
Help pane
Help group
Figure 1–91
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-61
EX 1-62 Excel Module 1 Creating a Worksheet and a Chart
3
• Type functions in the Search help box at
functions entered
in Search box
the top of the Help pane to enter the search
text (Figure 1–92).
Figure 1–92
4
• Press ENTER to display the search results
Q&A
(Figure 1–93).
Why do my search results differ?
If you do not have an Internet connection, your
results will reflect only the content of the Help
files on your computer. When searching for
help online, results also can change as content
is added, deleted, and updated on the online
Help webpages maintained by Microsoft.
Why were my search results not very helpful?
When initiating a search, be sure to check the
spelling of the search text; also, keep your
search specific to return the most accurate
results.
‘Excel functions
(by category)’ link
search
results
Figure 1–93
5
Close button
• Click the ‘Excel functions (by category)’, or
similar, link to display the Help information
associated with the selected topic
(Figure 1–94).
Help
information
Figure 1–94
6
• Click the Close button in the Help pane to close the pane.
• Click Home on the ribbon to display the Home tab.
Obtaining Help while Working in an Office App
You also can access the Help functionality
without first opening the Help pane and
initiating a search. For example, you may be
confused about how a particular command
works, or you may be presented with a dialog
box that you are not sure how to use.
If you want to learn more about a
command, point to its button and wait for the
ScreenTip to appear, as shown in Figure 1–95. If
the Help icon and ‘Tell me more’ link appear in
the ScreenTip, click the ‘Tell me more’ link (or
press f1 while pointing to the button) to open
the Help window associated with that command.
Dialog boxes also contain Help buttons, as
shown in Figure 1–96. Clicking the Help button
(or pressing f1) while the dialog box is displayed
opens a Help window, which will display help
contents specific to the dialog box, if available. If
no help file is available for that particular dialog
box, then the window will display the Help
home page.
As mentioned previously, the Tell me box
is integrated into the ribbon in Excel and most
other Office apps and can perform a variety of
functions, including providing easy access to
commands and help content as you type.
Format Painter
button
Help button in
ScreenTip
Figure 1–95
Help button in
dialog box
Figure 1–96
To Obtain Help Using the Tell Me Box
If you are having trouble finding a command in Excel, you can use the Tell me box to search for the
function you are trying to perform. As you type, the Tell me box will suggest commands that match the search
text you are entering. Why? You can use the Tell me box to access commands quickly you otherwise may be unable to find
on the ribbon. The following steps find commands related to headers and footers.
1
• Type header and footer in the Tell me box and watch the search results appear (Figure 1–97).
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-63
EX 1-64 Excel Module 1 Creating a Worksheet and a Chart
search text in
Tell Me box
commands related
to search text
Figure 1–97
To Save a Workbook with a Different File Name
To save a copy of the existing file, you can save the file with a new file name.
Why? You have finished working on the Frangold Real Estate Budget workbook and would like
to save a copy of the workbook with a new file name.
The following steps save the Frangold Real Estate Budget workbook with a new
file name.
1
Click File on the ribbon to open Backstage view.
2
Click Save As in Backstage view to display the Save As screen.
3
Type SC_EX_1_Frangold in the File name text box, replacing the existing file name.
4
Click the Save button to save the workbook with the new name.
To Sign Out of a Microsoft Account
Click File on the ribbon to open Backstage view.
2
Click Account to display the Account screen (Figure 1–98).
3
Click the Sign out link, which displays the Remove Account dialog box. If a Can’t
remove Windows accounts dialog box appears instead of the Remove Account dialog
box, click OK and skip the remaining steps.
Why does a Can’t remove Windows accounts dialog box appear?
If you signed in to Windows using your Microsoft account, then you also must sign out
from Windows rather than signing out from within Excel. When you are finished using
Windows, be sure to sign out at that time.
4
Click the Yes button (Remove Account dialog box) to sign out of your Microsoft
account on this computer.
Q&A
1
Q&A
If you are using a public computer or otherwise want to sign out of your
Microsoft account, you should sign out of the account from the Accounts screen in
Backstage view. Why? For security reasons, you should sign out of your Microsoft account
when you are finished using a public or shared computer. Staying signed in to your Microsoft
account might enable others to access your files.
The following steps sign out of a Microsoft account and exit the Excel program.
If you do not want to sign out of your Microsoft account or exit Excel, read these steps
without performing them.
Should I sign out of Windows after removing my Microsoft account?
When you are finished using the computer, you should sign out of Windows for
maximum security.
account currently
signed in to
Microsoft Office
Account screen
Sign out link
your software version
may differ
Account tab
Figure 1–98
5
Click the Back button in the upper-left corner of Backstage view to return to the document.
6
Click the Close button to close the workbook and exit Microsoft Excel. If
you are prompted to save changes, click Yes.
Summary
CONSIDER THIS: PLAN AHEAD
In this module you have learned how to create a real estate budget worksheet and chart.
Topics covered included starting Excel and creating a blank workbook, selecting a cell,
entering text, entering numbers, calculating a sum, using the fill handle, formatting
a worksheet, adding a pie chart, changing sheet tab names and colors, printing a
worksheet, using the AutoCalculate area, correcting errors, and obtaining help.
What decisions will you need to make when creating workbooks and charts in the future?
Use these guidelines as you complete the assignments in this module and create your own spreadsheets outside of this class.
1. Determine the workbook structure.
a) Determine the data you will need for your workbook.
b) Sketch a layout of your data and your chart.
2. Create the worksheet.
a) Enter titles, subtitles, and headings.
b) Enter data, functions, and formulas.
3. Format the worksheet.
a) Format the titles, subtitles, and headings using styles.
b) Format the totals.
c) Format the numbers.
d) Format the text.
e) Adjust column widths.
4. Create the chart.
a) Determine the type of chart to use.
b) Determine the chart title and data.
c) Determine the chart location
d) Format the chart.
Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-65
STUDENT ASSIGNMENTS
EX 1-66 Excel Module 1 Creating a Worksheet and a Chart
Apply Your Knowledge
Reinforce the skills and apply the concepts you learned in this module.
Changing the Values in a Worksheet
Note: To complete this assignment, you will be required to use the Data Files. Please contact your
instructor for information about accessing the Data Files.
Instructions: Start Excel. Open the workbook called SC_EX_1-1.xlsx (Figure 1–99a), which is
located in the Data Files. The workbook you open contains sales data for Delton Discount. You are
to edit data, apply formatting to the worksheet, and move the chart to a new sheet tab.
Perform the following tasks:
1. Make the changes to the worksheet described in Table 1–7. As you edit the values in the cells
containing numeric data, watch the totals in row 8, the totals in column H, and the chart
change.
Table 1–7 New Worksheet Data
Cell
Change Cell Contents To
A2
Monthly Departmental Sales
B5
13442.36
C7
115528.13
D5
24757.85
E6
39651.54
F7
29667.88
G6
19585.46
2. Change the worksheet title in cell A1 to the Title cell style and then merge and center it across
columns A through H.
3. Use buttons in the Font group on the Home tab on the ribbon to change the worksheet subtitle
in cell A2 to 14-point font and then merge and center it across columns A through H. Change
the font color of cell A2 to Blue, Accent 1, Darker 50%.
4. Name the worksheet, Department Sales, and apply the Blue, Accent 1, Darker 50% color to the
sheet tab (Figure 1–99b).
5. Move the chart to a new sheet called Sales Analysis Chart (Figure 1–99c). Change the chart title
to MONTHLY SALES TOTALS.
If requested by your instructor, on the Department Sales worksheet, replace Delton in cell A1
with your last name.
6. Save the workbook with the file name, SC_EX_1_Delton, and submit the revised workbook
(shown in Figure 1–99) in the format specified by your instructor and exit Excel.
7.
Besides the styles used in the worksheet, what other changes could you make to enhance the
worksheet?
(a) Worksheet before Formatting
(b) Worksheet after Formatting
(c) Pie Chart on Separate Sheet
Figure 1–99
STUDENT ASSIGNMENTS Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-67
STUDENT ASSIGNMENTS
EX 1-68 Excel Module 1 Creating a Worksheet and a Chart
Extend Your Knowledge
Extend the skills you learned in this module and experiment with new skills. You may
need to use Help to complete the assignment.
Creating Styles and Formatting a Worksheet
Note: To complete this assignment, you will be required to use the Data Files. Please contact your
instructor for information about accessing the Data Files.
Instructions: Start Excel. Open the workbook called SC_EX_1-2.xlsx, which is located in the Data
Files. The workbook you open contains sales data for Harolamer Electronics. You are to create
styles and format a worksheet using them.
Perform the following tasks:
1. Select cell A4. Use the New Cell Style command in the Cell Styles gallery open the Style dialog
box (Figure 1-100). Create a style that uses the Orange, Accent 2 font color (row 1, column 6).
Name the style, MyHeadings.
2. Select cell A5. Use the New Cell style dialog box to create a style that uses the Orange, Accent
2, Darker 50% (row 6, column 6) font color. Name the style, MyRows.
3. Select cell ranges B4:G4 and A5:A8. Apply the MyHeadings style to the cell ranges.
4. Select the cell range B5:G7. Apply the MyRows style to the cell range.
5. Name the sheet tab and apply a color of your choice.
If requested by your instructor, change the font color of the text in cells A1 and A2 to the color
of your eyes.
6. Save the workbook with the file name, SC_EX_1_Harolamer, and submit the revised workbook
in the format specified by your instructor, and then exit Excel.
7.
What other styles would you create to improve the worksheet’s appearance?
Figure 1–100
Expand Your World
Create a solution that uses cloud or web technologies by learning and
investigating on your own from general guidance.
Loan Calculator
Instructions: Start Excel. You are to determine how long it will take you to pay back
a loan. You decide to download and use one of the Excel templates to create your
worksheet.
Perform the following tasks:
1. Click New in Backstage view and then search for and click a template that can
calculate loans for an item you choose, such as a vehicle, mortgage, or general loan.
2. Enter fictitious (but realistic) information for a loan, including loan number,
lender, loan amount, annual interest rate, beginning date, and length (in years).
If the template you chose does not include a place for this information, add the
information in an appropriate location. Search the web to examine current interest
rates and typical loan durations.
3. Save the file as SC_EX_1_LoanCalculator, print the worksheet, and submit the
assignment in the format specified by your instructor and then exit Excel.
4.
Which template would you use if you wanted to plan and keep track of a
budget for a wedding?
In the Lab
Design and implement a solution using creative thinking and problem-solving
skills.
Create a Worksheet Comparing Laptops
Problem: You are shopping for a new laptop and want to compare the prices of three
laptops. You will compare laptops with similar specifications, but where the brands
and/or models are different.
Perform the following tasks:
Part 1: Create a worksheet that compares the type, specifications, and the price for
each laptop, as well as the costs to add an extended warranty. Use the concepts and
techniques presented in this module to calculate the average price of a laptop and
average cost of an extended warranty and to format the worksheet. Include a chart to
compare the different laptop costs. Submit your assignment in the format specified by
your instructor.
You made several decisions while creating the worksheet in this assignment:
how to organize the data, how to display the text, which calculations to use, and which
chart to use. What was your rationale behind each of these decisions?
Part 2:
STUDENT ASSIGNMENTS Excel Module 1
Creating a Worksheet and a Chart Excel Module 1 EX 1-69
Chapter
Introduction
After completing this chapter, you will be able to
Describe the basic features of an algorithm
Explain how hardware and software collaborate in
a computer’s architecture
Summarize a brief history of computing
Compose and run a simple Python program
1
A Not-So-Brief History of Computing Systems
A programmer typically starts by writing high-level language statements in a text editor.
The programmer then runs another program called a translator to convert the high-level
program code into executable code. Because it is possible for a programmer to make grammatical mistakes even when writing high-level code, the translator checks for syntax errors
before it completes the translation process. If it detects any of these errors, the translator
alerts the programmer via error messages. The programmer then has to revise the program.
If the translation process succeeds without a syntax error, the program can be executed
by the run-time system. The run-time system might execute the program directly on the
hardware or run yet another program called an interpreter or virtual machine to execute
the program. Figure 1-3 shows the steps and software used in the coding process.
Text editor
Translator
Syntax error messages
Create high-level
language program
User inputs
Run-time
system
Other error messages
Program
outputs
Figure 1-3
Software used in the coding process
exercises
1.
List two examples of input devices and two examples of output devices.
2.
What does the central processing unit (CPU) do?
3.
How is information represented in hardware memory?
4.
What is the difference between a terminal-based interface and a graphical user interface?
5.
What role do translators play in the programming process?
a Not-So-Brief history of Computing Systems
Now that we have in mind some of the basic ideas of computing and computer systems,
let’s take a moment to examine how they have taken shape in history. Figure 1-4 summarizes some of the major developments in the history of computing. The discussion that
follows provides more details about these developments.
9
Chapter 1
Introduction
approximate
Dates
Major Developments
Before 1800
•
Mathematicians discover and use algorithms
•
Abacus used as a calculating aid
•
First mechanical calculators built by Pascal and Leibniz
•
Jacquard’s loom
•
Babbage’s Analytical Engine
•
Boole’s system of logic
•
Hollerith’s punch card machine
•
Turing publishes results on computability
10
19 Century
th
1930s
•
Shannon’s theory of information and digital switching
1940s
•
First electronic digital computers
1950s
•
First symbolic programming languages
•
Transistors make computers smaller, faster, more durable, and less
expensive
•
Emergence of data processing applications
•
Integrated circuits accelerate the miniaturization of hardware
•
First minicomputers
•
Time-sharing operating systems
•
Interactive user interfaces with keyboard and monitor
•
Proliferation of high-level programming languages
•
Emergence of a software industry and the academic study of
computer science
•
First microcomputers and mass-produced personal computers
•
Graphical user interfaces become widespread
•
Networks and the Internet
•
Optical storage for multimedia applications, images, sound,
and video
•
World Wide Web, Web applications, and e-commerce
•
Laptops
•
Wireless computing, smartphones, and mobile applications
•
Computers embedded and networked in an enormous variety of cars,
household appliances, and industrial equipment
•
Social networking, use of big data in finance and commerce
•
Digital streaming of music and video
1960–1975
1975–1990
1990–2000
2000–present
Figure 1-4
Summary of major developments in the history of computing
A Not-So-Brief History of Computing Systems
Before Electronic Digital Computers
Ancient mathematicians developed the first algorithms. The word “algorithm” comes from
the name of a Persian mathematician, Muhammad ibn Musa al-Khwarizmi, who wrote
several mathematics textbooks in the ninth century. About 2,300 years ago, the Greek
mathematician Euclid, the inventor of geometry, developed an algorithm for computing the
greatest common divisor of two numbers.
[b] Pascal’s Calculator Image © Mary Evans/Photo Researchers, Inc.
[a] Abacus Image © Lim ChewHow, 2008. Used under
license from Shutterstock.com.
A device known as the abacus also appeared in ancient times. The abacus helped people
perform simple arithmetic. Users calculated sums and differences by sliding beads on a grid
of wires (see Figure 1-5a). The configuration of beads on the abacus served as the data.
Figure 1-5
Some early computing devices
11
Chapter 1
Introduction
[c] Jacquard’s Loom Image © Roger Viollet/Getty Images
12
Figure 1-5
(Continued)
In the seventeenth century, the French mathematician Blaise Pascal (1623–1662) built
one of the first mechanical devices to automate the process of addition (see Figure 1-5b).
The addition operation was embedded in the configuration of gears within the machine.
The user entered the two numbers to be added by rotating some wheels. The sum or output number appeared on another rotating wheel. The German mathematician Gottfried
Wilhelm Leibniz (1646–1716) built another mechanical calculator that included other
arithmetic functions such as multiplication. Leibniz, who with Newton also invented calculus, went on to propose the idea of computing with symbols as one of our most basic and
general intellectual activities. He argued for a universal language in which one could solve
any problem by calculating.
Early in the nineteenth century, the French engineer Joseph-Marie Jacquard (1752–1834)
designed and constructed a machine that automated the process of weaving (see Figure 1-5c).
Until then, each row in a weaving pattern had to be set up by hand, a quite tedious, errorprone process. Jacquard’s loom was designed to accept input in the form of a set of punched
cards. Each card described a row in a pattern of cloth. Although it was still an entirely
mechanical device, Jacquard’s loom possessed something that previous devices had lacked—
the ability to execute an algorithm automatically. The set of cards expressed the algorithm or
set of instructions that controlled the behavior of the loom. If the loom operator wanted to
produce a different pattern, he just had to run the machine with a different set of cards.
Chapter
2
SOFTWARE
DEVELOPMENT, Data
Types, and Expressions
After completing this chapter, you will be able to
Describe the basic phases of software development:
analysis, design, coding, and testing
Use strings for the terminal input and output of text
Use integers and floating-point numbers in arithmetic
operations
Construct arithmetic expressions
Initialize and use variables with appropriate names
Import functions from library modules
Call functions with arguments and use returned values
appropriately
Construct a simple Python program that performs inputs,
calculations, and outputs
Use docstrings to document Python programs
The Software Development Process
This chapter begins with a discussion of the software development process, followed by a
case study in which we walk through the steps of program analysis, design, coding, and testing. We also examine the basic elements from which programs are composed. These include
the data types for text and numbers and the expressions that manipulate them. The chapter
concludes with an introduction to the use of functions and modules in simple programs.
35
the Software Development process
There is much more to programming than writing lines of code, just as there is more to
building houses than pounding nails. The “more” consists of organization and planning,
and various conventions for diagramming those plans. Computer scientists refer to the
process of planning and organizing a program as software development. There are several
approaches to software development. One version is known as the waterfall model.
The waterfall model consists of several phases:
1.
Customer request—In this phase, the programmers receive a broad statement of
a problem that is potentially amenable to a computerized solution. This step is also
called the user requirements phase.
2.
analysis—The programmers determine what the program will do. This is some-
times viewed as a process of clarifying the specifications for the problem.
3.
Design—The programmers determine how the program will do its task.
4.
Implementation—The programmers write the program. This step is also called the
coding phase.
5.
Integration—Large programs have many parts. In the integration phase, these parts
are brought together into a smoothly functioning whole, usually not an easy task.
6.
Maintenance—Programs usually have a long life; a life span of 5 to 15 years is com-
mon for software. During this time, requirements change, errors are detected, and
minor or major modifications are made.
The phases of the waterfall model are shown in Figure 2-1. As you can see, the figure resembles a waterfall, in which the results of each phase flow down to the next. However, a mistake
detected in one phase often requires the developer to back up and redo some of the work in
the previous phase. Modifications made during maintenance also require backing up to earlier phases. Taken together, these phases are also called the software development life cycle.
Although the diagram depicts distinct phases, this does not mean that developers must
analyze and design a complete system before coding it. Modern software development
is usually incremental and iterative. This means that analysis and design may produce a
rough draft, skeletal version, or prototype of a system for coding, and then back up to earlier phases to fill in more details after some testing. For purposes of introducing this process, however, we treat these phases as distinct.
Programs rarely work as hoped the first time they are run; hence, they should be subjected
to extensive and careful testing. Many people think that testing is an activity that applies
only to the implementation and integration phases; however, you should scrutinize the
SOFTWARE DEVELOPMENT, Data Types, and Expressions
Chapter 2
Customer request
Verify
Analysis
36
Verify
Design
Verify
Implementation
Test
Integration
Test
Maintenance
Figure 2-1
The waterfall model of the software development process
outputs of each phase carefully. Keep in mind that mistakes found early are much less
expensive to correct than those found late. Figure 2-2 illustrates some relative costs of
repairing mistakes when found in different phases. These are not just financial costs but
also costs in time and effort.
Cost of
Correcting
a Fault
Analysis
Design
Implementation Integration
Maintenance
Software Development Phase
Figure 2-2
Relative costs of repairing mistakes that are found in different phases
The Software Development Process
Keep in mind that the cost of developing software is not spread equally over the phases.
The percentages shown in Figure 2-3 are typical.
Integration 8%
37
Implementation 8%
Design 8%
Analysis 8%
Maintenance 68%
Figure 2-3 Percentage of total cost incurred
in each phase of the development process
You might think that implementation takes the most time and therefore costs the most.
However, as you can see in Figure 2-3, maintenance is the most expensive part of software
development. The cost of maintenance can be reduced by careful analysis, design, and
implementation.
As you read this book and begin to sharpen your programming skills, you should remember
two points:
1.
There is more to software development than writing code.
2.
If you want to reduce the overall cost of software development, write programs
that are easy to maintain. This requires thorough analysis, careful design, and
a good coding style. We will have more to say about coding styles throughout
the book.
exercises
1.
List four phases of the software development process, and explain what they
accomplish.
2.
Jack says that he will not bother with analysis and design but proceed directly to
coding his programs. Why is that not a good idea?
Chapter 2
SOFTWARE DEVELOPMENT, Data Types, and Expressions
CaSe StuDy: Income Tax Calculator
38
Most of the chapters in this book include a case study that illustrates the software
development process. This approach may seem overly elaborate for small programs,
but it scales up well when programs become larger. The first case study develops a
program that calculates income tax.
Each year, nearly everyone with an income faces the unpleasant task of computing
his or her income tax return. If only it could be done as easily as suggested in this
case study! We start with the customer request phase.
request
The customer requests a program that computes a person’s income tax.
analysis
Analysis often requires the programmer to learn some things about the problem
domain, in this case, the relevant tax law. For the sake of simplicity, let’s assume the
following tax laws:
• All taxpayers are charged a flat tax rate of 20%.
• All taxpayers are allowed a $10,000 standard deduction.
• For each dependent, a taxpayer is allowed an additional $3,000 deduction.
• Gross income must be entered to the nearest penny.
• The income tax is expressed as a decimal number.
Another part of analysis determines what information the user will have to provide.
In this case, the user inputs are gross income and number of dependents. The
program calculates the income tax based on the inputs and the tax law and then
displays the income tax. Figure 2-4 shows the proposed terminal-based interface.
Characters in italics indicate user inputs. The program prints the rest. The inclusion
of an interface at this point is a good idea because it allows the customer and the
programmer to discuss the intended program’s behavior in a context understandable to both.
Enter the gross income: 150000.00
Enter the number of dependents: 3
The income tax is $26200.0
Figure 2-4
The user interface for the income tax calculator
(continues)
The Software Development Process
(continued )
Design
During analysis, we specify what a program is going to do. In the next phase, design,
we describe how the program is going to do it. This usually involves writing an algorithm. In Chapter 1, we showed how to write algorithms in ordinary English. In fact,
algorithms are more often written in a somewhat stylized version of English called
pseudocode. Here is the pseudocode for our income tax program:
Input the gross income and number of dependents
Compute the taxable income using the formula
Taxable income = gross income - 10000 - (3000 * number of dependents)
Compute the income tax using the formula
Tax = taxable income * 0.20
Print the tax
Although there are no precise rules governing the syntax of pseudocode, in your
pseudocode you should strive to describe the essential elements of the program in a
clear and concise manner. Note that this pseudocode closely resembles Python code,
so the transition to the coding step should be straightforward.
Implementation (Coding)
Given the preceding pseudocode, an experienced programmer would now find it easy
to write the corresponding Python program. For a beginner, on the other hand, writing
the code can be the most difficult part of the process. Although the program that follows is simple by most standards, do not expect to understand every bit of it at first.
The rest of this chapter explains the elements that make it work, and much more.
"""
Program: taxform.py
Author: Ken Lambert
Compute a person’s income tax.
1. Significant constants
tax rate
standard deduction
deduction per dependent
2. The inputs are
gross income
number of dependents
3. Computations:
taxable income = gross income - the standard
deduction - a deduction for each dependent
income tax = is a fixed percentage of the taxable income
4. The outputs are
the income tax
"""
(continues)
39
Chapter 2
SOFTWARE DEVELOPMENT, Data Types, and Expressions
(continued )
40
# Initialize the constants
TAX_RATE = 0.20
STANDARD_DEDUCTION = 10000.0
DEPENDENT_DEDUCTION = 3000.0
# Request the inputs
grossIncome = float(input("Enter the gross income: "))
numDependents = int(input("Enter the number of dependents: "))
# Compute the income tax
taxableIncome = grossIncome - STANDARD_DEDUCTION - \
DEPENDENT_DEDUCTION * numDependents
incomeTax = taxableIncome * TAX_RATE
# Display the income tax
print("The income tax is $" + str(incomeTax))
testing
Our income tax program can run as a script from an IDLE window. If there are no syntax
errors, we will be able to enter a set of inputs and view the results. However, a single
run without syntax errors and with correct outputs provides just a slight indication of a
program’s correctness. Only thorough testing can build confidence that a program is
working correctly. Testing is a deliberate process that requires some planning and discipline on the programmer’s part. It would be much easier to turn the program in after the
first successful run to meet a deadline or to move on to the next assignment. But your
grade, your job, or people’s lives might be affected by the slipshod testing of software.
Testing can be performed easily from an IDLE window. The programmer just loads the
program repeatedly into the shell and enters different sets of inputs. The real challenge is coming up with sets of inputs that can reveal an error. An error at this point,
also called a logic error or a design error, is an unexpected output.
A correct program produces the expected output for any legitimate input. The tax
calculator’s analysis does not provide a specification of what inputs are legitimate, but
common sense indicates that they would be numbers greater than or equal to 0. Some
of these inputs will produce outputs that are less than 0, but we will assume for now that
these outputs are expected. Even though the range of the input numbers on a computer
is finite, testing all of the possible combinations of inputs would be impractical. The challenge is to find a smaller set of inputs, called a test suite, from which we can conclude
that the program will likely be correct for all inputs. In the tax program, we try inputs of
0, 1, and 2 for the number of dependents. If the program works correctly with these,
we can assume that it will work correctly with larger values. The test inputs for the gross
income are a number equal to the standard deduction and a number twice that amount
(10000 and 20000, respectively). These two values will show the cases of a minimum
(continues)
Strings, Assignment, and Comments
(continued )
expected tax (0) and expected taxes that are less than or greater than 0. The program
is run with each possible combination of the two inputs. Table 2-1 shows the possible
combinations of inputs and the expected outputs in the test suite.
41
Number of Dependents
Gross Income
expected tax
0
10000
0
1
10000
–600
2
10000
–1200
0
20000
2000
1
20000
1400
2
20000
800
table 2-1
The test suite for the tax calculator program
If there is a logic error in the code, it will almost certainly be caught using these data.
Note that the negative outputs are not considered errors. We will see how to prevent
such computations in the next chapter.
Strings, assignment, and Comments
Text processing is by far the most common application of computing. E-mail, text messaging, Web pages, and word processing all rely on and manipulate data consisting of strings
of characters. This section introduces the use of strings for the output of text and the documentation of Python programs. We begin with an introduction to data types in general.
Data Types
In the real world, we use data all the time without bothering to consider what kind of data
we’re using. For example, consider this sentence: “In 2007, Micaela paid $120,000 for her house
at 24 East Maple Street.” This sentence includes at least four pieces of data—a name, a date,
a price, and an address—but of course you don’t have to stop to think about that before you
utter the sentence. You certainly don’t have to stop to consider that the name consists only of
text characters, the date and house price are numbers, and so on. However, when we use data
in a computer program, we do need to keep in mind the type of data we’re using. We also need
to keep in mind what we can do with (what operations can be performed on) particular data.
In programming, a data type consists of a set of values and a set of operations that can be
performed on those values. A literal is the way a value of a data type looks to a programmer. The programmer can use a literal in a program to mention a data value. When the