CAMBRIDGE LOWER SECONDARY COMPUTING 8: LEARNER’S BOOK ANSWERS
Learner’s Book
answers
Note to the teacher: Please note that there are always answers to the Questions and Check your progress
features in the Learner’s Book. There may be suggested answers to some questions for Getting started,
Activity, Unplugged activity, Programming task and Practical task features if appropriate.
Programming task 1.7
Unit 1
Investigate 1: Condition: (colour = "red"),
if true value = 1, if false value = 2; Boolean
operator: NOT
Questions 1.1
1
To design algorithms or programs
2
Program code has syntax that has to
be followed, whereas pseudocode is
language-independent
Investigate 2: Conditions: (colour = "red",
colour = "blue"), if true value = 1,
if false value = 2; Boolean operator: OR
3
All are valid
Predict 2: 1
4
The first is not valid because the text to be
output is not in double quotation marks – it is
an English statement and is not like code
Investigate 3: Condition 1: (colour1 = "red",
colour2 = "blue"), if true value = 1, if false check
next condition; condition 2: (colour2 = "red",
colour1 = "purple"), if true value = 2, if false end
statement; Boolean operators: AND, OR
Predict 1: 1
Unplugged activity 1.2
1
value1
10
2
value2
12
3
value3
176
4
value4
44
100
Predict 3:
88
1
1
Any command such as OUTPUT,
PRINT, WRITE
2
It does not use commands or syntax for one
specific language, and it can be understood
by all programmers who can write high-level
language programs
3
Equals (=) and back arrow (←)
4
first, second, third
5
a
b
2
2
1
3
0
Questions 1.3
Questions 1.2
10
1
15
c
99
d
0
1
(1) Condition, (2) code to run when true and
(3) code to run when false
2
IF
3
"Smaller"
4
a
"second"
b
"same"
c
When both values are the same
d
When the first number is the larger
e
When the second number is the larger
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CAMBRIDGE LOWER SECONDARY COMPUTING 8: LEARNER’S BOOK ANSWERS
5
a
"The first ever computer was as big as a room."
b
"Why was the computer sneezing?"
"It had a virus."
c
Nothing – there will be no output
d
Include an ELSE statement
Questions 1.4
1
Looks for a value in a set of data, items or objects
2
For example: a search engine, looking for a file, looking for a user’s details
3
Computers need to find values in sets of data
4
Hundreds
5
No, it depends on the data
6
One after the other in a line
7
It looks at each item in turn from the first to the last
8
Compare search data with "cat": not found; compare it with "rabbit": not found; compare it
with "mouse": not found; compare it with "sheep": not found; compare it with "horse": found.
(Note: learners may use ‘look at’ or similar instead of ‘compare’)
9
Compare search data with 3: not found; compare it with 44: not found; compare it with 9: not found;
compare it with 50: not found; compare it with 19: not found; compare it with 2: not found; no items
left – item not found. (Note: learners may use ‘look at’ or similar instead of ‘compare’)
Questions 1.5
1
if
2
Indent the code
3
0 or 1
4
"Hamster"
5
20
6
0
7
When the first condition is false
8
For example:
year = input("Enter your year group")
if year == "7":
print("This is your first year")
elif year == "8":
print("I hope your second year is enjoyable")
else:
print("You're the oldest year now")
2
Victoria Ellis & Sarah Lawrey © Cambridge University Press & Assessment 2023
CAMBRIDGE LOWER SECONDARY COMPUTING 8: LEARNER’S BOOK ANSWERS
Programming task 1.18
Questions 1.9
1
Both output statements or calculations
1
Breaking something down into smaller pieces
2
The declaration line for the constant ‘cost’
2
Split it into smaller sub-problems
3
Both output statements
3
To make them easier to solve
4
The declaration line for the constant ‘message’
4
To make them easier to program, to identify
repeated code, to divide the problem between
multiple programmers, to increase the speed
of writing the program
Questions 1.6
1
The data held in a constant cannot change,
but the data held in a variable can change
Questions 1.10
2
An identifier and a value stored in them
1
Repeating
3
So the value cannot be accidentally changed,
to avoid mistakes by writing the data value
incorrectly and so that you only need to
change the value once and it will change in all
places it is used
2
Repeating development in cycles of
programming, then testing, then changing
or adding to the program, then testing and
so on . . . doing this repeatedly until the
program is finished
Questions 1.7
Questions 1.11
1
True and false, or 1 and 0
1
Normal, invalid and boundary
2
"True" is a string while True is a Boolean
data type
2
To make sure it always works with different
test data types
3
a
c
e
3
To make sure all valid data is accepted,
all boundary data is accepted or rejected as
required and that all invalid data is rejected
4
cost = real (or float), afford = Boolean
4
For example: it must include multiple numbers
that are the same, the smallest number
in different positions (first to fourth) and
the largest number in different positions
(first to fourth)
string
integer
string
b
d
f
real
Boolean
string
Questions 1.8
1
A set of pre-written sub-routines that you can
use in your program
2
To save programmers time, so programmers
do not need to write sub-routines that have
already been written by someone else
3
3
Anyone can write one and you don’t know
what the code does, so you need to make sure
they do not contain malware like viruses
4
import
5
math.floor(44.56)
6
Round the number in the brackets up to the
next whole number
7
9999
Questions 1.12
1
Wirelessly, using radio waves
2
Numbers and strings (and others)
3
So that you do not pick up transmissions
from other micro:bits, or transmit data to
other micro:bits
4
In a variable
5
Any way you would use any other data,
for example, in calculations, in selection
statements and in conditional statements
10000
Check your progress 1
8
Random
1
9
100, 101, 102, 103
All four answers (A, B, C and D)
are correct. One mark per correct answer. [4]
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CAMBRIDGE LOWER SECONDARY COMPUTING 8: LEARNER’S BOOK ANSWERS
2
11
3
C
4
It searches a set of data in a program for a specific value
[1]
5
It starts by checking the first item in the list, then it checks each item in turn until the item is
found or no items are left
[2]
The first number (12) is checked; this is not 33, so the next number (3) is checked; this is not 33,
so the next number (33) is checked; this is 33, so the search stops
[2]
7
D
==
[1]
8
B
!=
[1]
9
aThe program written should take one user’s name as input, take that user’s age as input,
convert to integer or other appropriate data type, then take a second user’s name and age in
the same way.
For example:
6
[1]
[1]
1005
user1Name = input("Enter user 1's name")
user1Age = int(input("Enter user 1's age"))
user2Name = input("Enter user 2's name")
user2Age = int(input("Enter user 2's age"))
b
[4]
The program written should use an IF statement, check if the ages are the same, output that
they are the same if so, check if user 1 is older and output a name if true, check if user 2 is
older and output name if true.
For example:
user1Name = input("Enter user 1's name")
user1Age = int(input("Enter user 1's age"))
user2Name = input("Enter user 2's name")
user2Age = int(input("Enter user 2's age"))
if user1Age == user2Age:
print(user1Name, "and", user2Name, "are the same age")
elif user1Age > user2Age:
print(user1Name, "is older")
else:
print(user2Name, "is older")
10 Radio
[1]
11 a
b
c
d
e
10
20
No data would be transferred because micro:bit 2 does not have a Button A
An image of a heart is displayed
An X is displayed
[1]
[1]
[1]
[1]
[1]
12 Write a section or part of the code; test the section of code; edit the section of code to fix
errors or write the next section of code; and repeat until finished
[4]
13 aProblems are broken down or split into smaller sub-problems
[1]
b
4
[5]
Any two from: Sub-problems are easier to solve and manage. Problems can be divided between
different people. Different sub-problems can be solved at the same time, which saves time.
[2]
Victoria Ellis & Sarah Lawrey © Cambridge University Press & Assessment 2023
CAMBRIDGE LOWER SECONDARY COMPUTING 8: LEARNER’S BOOK ANSWERS
5
Unit 2
Practical task 2.2
1
Profit increases to $38, so $3 more profit
2
Profit decreases to $39, so $3 less profit
3
Profit increases to $40.50, so $13.50
more profit
Practical task 2.3
1
$2.90
2
50
Questions 2.1
1
The data will not be useful if it is not suitable
2
It may not be possible to use the data for
its intended purpose, or it could lead to
something negative happening, for example
a person being given the wrong task
6
Questions 2.2
Helps us gather data
from people
Record
A collection of all the
fields about a single
object in the database –
a single row in the table
Validation
A collection of the data
about one aspect of
every record – a single
column in the table
Data
collection
form
Rules for the data that
is entered into a field
[4]
Validation
rule
Description
Length
check
This rule checks how many
characters have been entered.
1
A paper-based or digital form that is used to
collect data for a purpose
Range
check
This rule checks whether the
data entered is within a range
of values.
2
Any three from: presence check, format check,
length check, range check
Presence
check
This rule checks whether data
has been entered into a field.
3
To make sure that the data collected
is accurate
[3]
7
Check your progress 2
1
2
3
4
5
Field
To provide a realistic copy of how a
real-life system or scenario works
[1]
Any two from: flight simulator,
surgery simulator, driving simulator
[2]
The information that is output and the
options that are given by the simulator
[1]
It changes the values in a spreadsheet to
see what effect the changes have on other
values in the spreadsheet in order to find
the outcome to a what-if question
Any two from: Whether all the data that
is stored is necessary; whether the data is
accurate; whether validation has been set
for the data that will be entered to make
sure that all of the data is complete and
correct; whether the data collection form
is easy to use and has clear instructions
for entering the data
[2]
Unit 3
Questions 3.1
[2]
1
A small number of devices
2
Close together, normally in the same room
3
The user or company that created the PAN
Victoria Ellis & Sarah Lawrey © Cambridge University Press & Assessment 2023
CAMBRIDGE LOWER SECONDARY COMPUTING 8: LEARNER’S BOOK ANSWERS
Questions 3.2
5
1
Two or more devices
2
Normally in the same building
3
The user or company that created the LAN
[3]
It will quarantine it or delete it
[1]
Questions 3.3
6
1
Any number of devices
2
Normally in different buildings across a town,
city or country
Unit 4
3
Some may belong to the user or company,
and some may belong to the internet
service provider
Questions 3.4
1
Wired
2
Wired
3
Wireless
4
Wired
Questions 4.1
1
RAM and ROM
2
RAM
3
ROM
4
a
ROM
b
The computer needs the same instructions
to boot up each time
Questions 4.2
1
Any two from: Providing an interface, memory
management, managing user accounts,
managing files, running application software,
managing input and output devices
2
Interface
3
Utility software
Check your progress 3
1
2
3
4
6
Any three from: It can be hardware- or
software-based. It checks data coming
into the computer. It uses rules for data –
if the data does not meet the rules the
firewall will block it. It can help prevent
hackers stealing data.
Any one from: They both usually use at
least some wired connections. A small
WAN could contain a similar number of
devices to a large LAN.
[1]
Any one from: The user or company owns
all the network hardware. They can
contain a similar number of devices.
They can both be created using only
wireless connections.
[1]
Questions 4.3
Any two from: The network hardware
belongs to the user in a PAN, but it may
belong to someone else in a WAN.
The devices are all in the same room in
a PAN, but they are usually in different
buildings in a WAN. A PAN contains
only a small number of devices, but a
WAN can contain a large number
of devices.
[2]
sender; receiver; copy; compares;
original; errors
[6]
1
0011 (or 11)
2
0111 (or 111)
3
1100
4
15
Unplugged activity 4.3
•
00110011 in denary is 51.
•
10101010 in denary is 170.
Activity 4.4
YOU ARE AWESOME!
Victoria Ellis & Sarah Lawrey © Cambridge University Press & Assessment 2023
CAMBRIDGE LOWER SECONDARY COMPUTING 8: LEARNER’S BOOK ANSWERS
Questions 4.4
2
Any one from: RAM is volatile and ROM
is non-volatile. RAM stores data currently
in use and ROM stores instructions to boot
up the computer. The data in RAM
changes all the time, but the data in
ROM never changes.
[1]
It allows the user to interact with the
hardware of the computer
[1]
Any three from: Provides an interface;
memory management; managing user
accounts; managing files; running
application software; managing input
and output devices
[3]
aA standard set of binary values,
one to represent each character
(letter, number or symbol)
[1]
1
A standard set of binary values, one to
represent each character (letter, number
or symbol)
2
Because every character needs to have a
different binary value, and uppercase letters
and lowercase letters are different characters
3
Data compression
4
3
Questions 4.5
1
To show the outputs that will result from all
the possible inputs into a logic gate
2
Because the NOT gate only has 1 input so
there can only be two possible input values
5
b
Questions 4.6
1
It can use the data it collects to adapt its own
rules to make different decisions
2
No
3
Yes
Check your progress 4
1
7
Any one from: ASCII;
extended ASCII; Unicode
[1]
6
AND
[1]
7
A standard AI system uses preprogrammed
rules to make decisions, whereas an AI
system with machine learning capabilities
is able to adapt its own rules based on
what it experiences and can make
different decisions in future
[2]
Any one from: They both store data.
They are both examples of primary memory.
The CPU accesses both directly.
[1]
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