Assigning the result of an expression
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. In TotalToPay ← NumberOfHours * HourlyRate, what happens first?
2. Which line stores the result of a calculation in TotalToPay?
3. Counter currently holds 4. What does Counter hold after Counter ← Counter + 1 ?
4. Which statement describes Counter ← Counter + 1 correctly?
5. HourlyRate holds 8 and NumberOfHours holds 5. After TotalToPay ← NumberOfHours * HourlyRate, what do the variables hold?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1TotalToPay ← NumberOfHours * HourlyRate | AThe arrow is the wrong way round. The variable that receives the result must be on the left and the expression on the right: TotalToPay ← NumberOfHours * HourlyRate. | |
| 2Counter ← Counter + 1 | BTakes the current value of Counter, adds 1, then stores the new value back in Counter, replacing the old one | |
| 3Copying the value of one variable into another variable | CBackupScore ← Score | |
| 4The expression on the right is calculated before anything is stored in the variable on the left | DThe expression is on the left of the arrow, so the result has nowhere to be stored. It should be Counter ← Counter + 1. | |
| 5NumberOfHours * HourlyRate ← TotalToPay | EWorks out NumberOfHours multiplied by HourlyRate first, then stores the result in TotalToPay | |
| 6Counter + 1 ← Counter | FArea ← Length * Width |
C
Definitions
TotalToPay ← NumberOfHours * HourlyRate
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
TotalToPay ← NumberOfHours _ HourlyRate
2.
Counter ← 5
Counter ← _______ + 1
OUTPUT Counter
3.
Lives ← 3
Lives ← Lives _ 1
4.
Score ← 10
Backup ← _____
5.
Total _ Price * Quantity
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
Hours ← 8
B
12.5 ← Rate
C
Total ← Hours * Rate
D
OUTPUT Total
Question 2
A
Counter ← 0
B
Counter ← Counter + 1
C
Counter ← Count + 1
D
OUTPUT Counter
Question 3
A
Hours = 6
B
Rate ← 11.5
C
TotalToPay ← Hours * Rate
Question 4
A
Length ← 5
B
Width ← 3
C
Area ← Length * Width
D
Perimeter ← 2 * Length + Width
Question 5
A
First ← 10
B
Second ← 20
C
First ← Backup
D
OUTPUT Backup
Answer Key
Assigning the result of an expression
Section A: Quick Questions
Q1
B — NumberOfHours * HourlyRate is worked out
Q2
A — TotalToPay ← NumberOfHours * HourlyRate
Q3
A — 5
Q4
B — It uses the old value of Counter, then replaces it with the new result
Q5
A — TotalToPay is 40, and NumberOfHours and HourlyRate are unchanged
Section B: Match the Pairs
Q1
TotalToPay ← NumberOfHours * HourlyRate → Works out NumberOfHours multiplied by HourlyRate first, then stores the result in TotalToPay
Q2
Counter ← Counter + 1 → Takes the current value of Counter, adds 1, then stores the new value back in Counter, replacing the old one
Q3
Copying the value of one variable into another variable → BackupScore ← Score
Q4
The expression on the right is calculated before anything is stored in the variable on the left → Area ← Length * Width
Q5
NumberOfHours * HourlyRate ← TotalToPay → The arrow is the wrong way round. The variable that receives the result must be on the left and the expression on the right: TotalToPay ← NumberOfHours * HourlyRate.
Q6
Counter + 1 ← Counter → The expression is on the left of the arrow, so the result has nowhere to be stored. It should be Counter ← Counter + 1.
Section C: Definitions
Q1
TotalToPay ← NumberOfHours * HourlyRate — The expression on the right is worked out first, then its result is stored in the variable on the left, replacing any old value that variable held.Section D: Fill in the Blanks
Q1
TotalToPay ← NumberOfHours * HourlyRateQ2
Counter ← 5
Counter ← Counter + 1
OUTPUT CounterQ3
Lives ← 3
Lives ← Lives - 1Q4
Score ← 10
Backup ← ScoreQ5
Total ← Price * QuantitySection E: Spot the Error
Q1
B — The variable being assigned to must be on the left of the arrow and the value on the right. It should be Rate ← 12.5.
Q2
C — The expression must use the variable Counter, whose old value is read and then replaced. Count was never declared or given a value. It should be Counter ← Counter + 1.
Q3
A — Cambridge pseudocode assigns with the ← arrow, not the = sign. It should be Hours ← 6.
Q4
D — Multiplication is worked out before addition, so this only doubles Length. Brackets are needed so the expression is Perimeter ← 2 * (Length + Width).
Q5
C — To copy First into Backup, the variable receiving the value goes on the left. Here Backup has no value yet and First would be overwritten. It should be Backup ← First.