Variables in an algorithm

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. What does SET score TO 0 do in an algorithm?

A It prints the word score on the screen

B It stores the value 0 in a variable called score

2. Which one is a variable name?

A lives

B TO

3. Which step makes a counter go up by one?

A ADD 1 to score

B SET score TO score

4. score is 0. After SET score TO 5, what is score?

A 5

B 0

5. A variable can only ever hold one value and can never change.

A True: it is fixed once it is made

B False: its value can be set and changed

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1SET score TO 0		AThe variable name and value are swapped. The name score should come after SET and the value 0 after TO: SET score TO 0.
2ADD 1 TO score		BThe steps are in the wrong order. The variable is changed before it has a starting value, so the counter would be reset to 0 and the count lost. SET should come first.
3A counter variable starts at zero before counting begins		CSET lives TO 3 ADD 1 TO lives
4A variable can store a value that changes later in the algorithm		DSET lapCount TO 0
5ADD 1 TO score SET score TO 0		EMakes a variable called score and gives it the starting value 0
6SET 0 TO score		FChanges the variable score by making its stored value one bigger

Definitions

SET score TO 0

Fill in the Blanks

Complete each line of code by filling in the missing parts.

___ score TO 0

SET score __ 0

SET score TO _

SET score TO 0 ADD 1 TO _____ SHOW score

SET count TO 0 REPEAT 3 TIMES ___ 1 TO count

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A SET score TO 0

B REPEAT 3 TIMES

C ADD 1 TO points

D DISPLAY score

Question 2

A SET lives TO 3

B SET score TO 0

C ADD 1 TO score

D DISPLAY scores

Question 3

A SET steps TO 0

B ADD 1 TO steps

C ADD steps TO 1

D DISPLAY steps

Question 4

A SET count TO 0

B ADD 1 count

C ADD 1 TO count

D DISPLAY count

Question 5

A SET lives TO 3

B SUBTRACT 1 FROM lives

C SUBTRACT 1 FROM lives

D DISPLAY 3

Answer Key

Variables in an algorithm

Section A: Quick Questions

B — It stores the value 0 in a variable called score

A — lives

A — ADD 1 to score

A — 5

B — False: its value can be set and changed

Section B: Match the Pairs

SET score TO 0 → Makes a variable called score and gives it the starting value 0

ADD 1 TO score → Changes the variable score by making its stored value one bigger

A counter variable starts at zero before counting begins → SET lapCount TO 0

A variable can store a value that changes later in the algorithm → SET lives TO 3 ADD 1 TO lives

ADD 1 TO score SET score TO 0 → The steps are in the wrong order. The variable is changed before it has a starting value, so the counter would be reset to 0 and the count lost. SET should come first.

SET 0 TO score → The variable name and value are swapped. The name score should come after SET and the value 0 after TO: SET score TO 0.

Section C: Definitions

SET score TO 0 — A variable is a named place that stores a value. SET gives it a value, like 0, and later steps can change it, such as ADD 1 to score, so it works as a counter.

Section D: Fill in the Blanks

SET score TO 0

SET score TO 0
ADD 1 TO score
SHOW score

SET count TO 0
REPEAT 3 TIMES
  ADD 1 TO count

Section E: Spot the Error

C — The variable was named score, but this line adds to points, which was never set. It should be ADD 1 TO score.

D — There is no variable called scores. The variable is named score, so the line should be DISPLAY score.

C — The words are in the wrong order. The number goes first and the variable goes last, so it should be ADD 1 TO steps.

B — The word TO is missing. The step should be ADD 1 TO count so it is clear which variable gets the 1 added.

D — This shows the number 3 instead of the variable. Lives has changed to 1, so the line should be DISPLAY lives.