4.1 Historical Numeration Systems Basics of Numeration The various ways of symbolizing and working with the counting numbers are called numeration systems. The symbols of a numeration system are called numerals. Tally sticks and tally marks have been used for a long time. Each mark represents one item. For example, eight items are tallied by writing the following: Ancient Egyptian Numeration Counting by Grouping Counting by grouping allows for less repetition of symbols and makes numerals easier to interpret. The size of the group is called the base (usually ten) of the number system. Simple Grouping The ancient Egyptian system is an example of a simple grouping system. It uses ten as its base and the various symbols are shown below. Example 1: Egyptian Numeral Write the number below in our system. 1 Example 2: Egyptian Numeral Example 3: Egyptian Numeral Example 4: Egyptian Numeral Assignment 32 pg. 144: 1 - 14 ODD, 35-46 ODD, 47 2 Ancient Roman Numeration The ancient Roman method of counting is a modified grouping system. It uses ten as its base, but also has symbols for 5, 50, and 500. The Roman system also has a subtractive feature which allows a number to be written using subtraction. A smaller-valued symbol placed immediately to the left of the larger value indicated subtraction. The ancient Roman numeration system also has a multiplicative feature to allow for bigger numbers to be written. A bar over a number means multiply the number by 1000. A double bar over the number means multiply by 10002 or 1,000,000 Example : Roman Numeral Write the number below in our system. MCMXLVII Example 5: Roman Numeral Example 6: Roman Numeral Assignment 33 pg. 144: 15-22 ALL 3 Ancient Chinese Numerals Traditional Chinese Numeration – Multiplicative Grouping A multiplicative grouping system involves pairs of symbols, each pair containing a multiplier and then a power of the base. The symbols for a Chinese version are shown below. Example 7: Chinese Numeral Example 8: Chinese Numeral Assignment 34 pg. 144: 23-30 ALL, 31, 33, 53-63 ODD 4 Section 4-2 – More Historical Number Systems An additive system is one in which the number represented by a set of numerals is simply the sum of the values of the numerals. Examples: Egyptian hieroglyphics and Roman numerals. Basics of Positional Numeration A positional system is In a positional numeral, each symbol (called a digit) conveys two things: 1. Face value – 2. Place value – . To work successfully, a positional system must have a symbol for zero to serve as a placeholder in case one or more powers of the base is not needed. Hindu-Arabic Numeration One system that uses positional form is our system, the Hindu-Arabic system. The place values in a Hindu-Arabic numeral, from right to left, are 1, 10, 100, 1000, and so on. The three 4s in the number 45,414 all have the same face value but different place values. Digits: In the Hindu-Arabic system, the digits are 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 Positions: In the Hindu-Arabic system, the positional values or place values are … 105, 104, 103, 102, 10, 1 Example: Fill in the place value for each digit 7, 5 4 1, 7 2 5 5 Babylonian Numeration Oldest known numeration system that resembled a place-value system Developed in about 2500 B.C. Resembled a place-value system with a base of 60, a sexagesimal system Not a true place-value system because it lacked a symbol for zero The lack of a symbol for zero led to a great deal of ambiguity and confusion The digits in a base 60 system represent the number of 1s, the number of 60s, the number of 3600s, and so on. The Babylonians used only two symbols to create all the numbers between 1 and 59. ▼=1 and ‹ =10 The positional values in the Babylonian system are …, (60)3, (60)2, 60, 1 Example 1: Example 2: 6 Example: Interpret each Babylonian numeral. a) ‹ ‹ ‹ ▼ ▼ ▼ ▼ b) ▼ ▼ ‹ ‹ ‹ ▼ ▼ ▼ ▼ ▼ Example: Write 7223 as a Babylonian numeral. Assignment 35 page 150: #3,9,11,17,21,23,25,27,29 7 Mayan Numeration The ancient Mayans used a base 20 numeration system, but with a twist. Normally the place values in a base 20 system would be 1s, 20s, 400s, 8000s, etc. Instead, the Mayans used 360s as their third place value. Numerals are written vertically. Units position is on the bottom. Numeral in bottom row is multiplied by 1. Numeral in second row is multiplied by 20. Numeral in third row is multiplied by 18 × 20, or 360. Numeral in fourth row is multiplied by 18 × 202, or 7200, and so on. The positional values in the Mayan system are …, 18 × (20)3, 18 × (20)2, 20, 1 or …, 144,000, 7200, 20, 1 Example 3: Example 4: 8 Example: Write the number below in our system. Example: Write 4025 as a Mayan numeral. Greek Numeration The classical Greeks used a ciphered counting system. They had 27 individual symbols for numbers, based on the 24 letters of the Greek alphabet, with 3 Phoenician letters added. Example: Interpret each Greek numeral. a) b) Assignment 36 page 150 #1,5,7,13,15,19, 31-47 ODD 9 4.3 - Arithmetic in the Hindu-Arabic System Expanded Form By using exponents, numbers can be written in expanded form in which the value of the digit in each position is made clear. Example 1: Example 2: Example 3: Distributive Property: For all real numbers a, b, and c, b a c a b c a. For example, 3 10 2 10 3 2 10 4 4 4 5 104. Example 4: 10 Example 5: Example 6: Example 7: Assignment 37 page 157 #1-25 odd 11 Historical Calculation Devices Because our numeration system is based on powers of ten, it is called the decimal system, from the Latin word decem, meaning ten. One of the oldest devices used in calculations is the abacus. It has a series of rods with sliding beads and a dividing bar. Reading from right to left, the rods have values of 1, 10, 100, 1000, and so on. The bead above the bar has five times the value of those below. Beads moved towards the bar are in “active” position. Example: Which number is shown above? The Lattice Method was an early form of a paper-and-pencil method of calculation. This method arranged products of single digits into a diagonalized lattice. Example: Find the product 38∙ 794 by the lattice method. Step 1: Set up the grid to the right. Step 2: Fill in products Step 3: Add diagonally right to left and carry as necessary to the next diagonal. Step 4: Assignment 38 page 158 #27-38 all, 45-52 all 12 4.4 - Conversion Between Number Bases General Bases Conversions We consider bases other than ten. Bases other than ten will have a spelled-out subscript as in the numeral 54eight. When a number appears without a subscript assume it is base ten. Note that 54eight is read “five four base eight.” Do not read it as “fifty-four.” Powers of Alternative Bases Fourth Power Third Power Second Power First Power Zero Power Base two 16 8 4 2 1 Base five 625 125 25 5 1 Base seven 2401 343 49 7 1 Base eight 4096 512 64 8 1 65,536 4096 256 16 1 Base sixteen Example: Convert 1342five to decimal form. Example: Convert 2134five to decimal form. To convert from another base to decimal form: Start with the first digit on the left and multiply by the base. Then add the next digit, multiply again by the base, and so on. The last step is to add the last digit on the right. Do not multiply it by the base. Example: Use the calculator shortcut to convert 244314five to decimal form. Example: Use the calculator shortcut to convert 432134five to decimal form. 13 Example: Convert 497 from decimal form to base five Example: Convert 6343seven to decimal for by expanding in powers, and using the calculator shortcut. . Example: Convert 7508 to base seven. Example: Convert 364seven to base five. Assignment 39 page 165 # 1-45 odd 14 Computer Mathematics Computers and many other electronic devices use three numeration systems: Binary – base 2 Uses only the digits 0 and 1. Can be represented with electronic switches that are either off (0) or on (1). All computer data can be converted into a series of single binary digits. Each binary digit is known as a bit. Octal – base 8 Eight bits of data are grouped to form a byte American Standard Code for Information Interchange (ASCII) code. The byte 01000001 represents A. The byte 01100001 represents a. Hexadecimal – base 16 Used to create computer languages: HTML (Hypertext Markup Language) CSS (Cascading Style Sheets). Both are used heavily in creating Internet web pages. Computers easily convert between binary (base 2), octal (base 8), and hexadecimal (base 16) numbers. Example: Convert 111001two to decimal form. Example: Convert 9583 to octal form. 15 Example: Convert FA5sixteen to decimal form. Example: Convert 748 from decimal to hexadecimal form. Example: Convert 473eight to binary form. Example: Convert 10011110two to octal form. Example: Convert 8B4Fsixteen to binary form. Assignment 40 page 166 # 47-95 odd 16