Following a flowchart to predict the result

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. Where do you begin when you follow a flowchart?

A At the first diamond

B At the Start oval

2. How do you move from one shape to the next?

A Follow the arrows

B Jump to any shape you like

3. You reach a diamond that asks 'Is score > 10?' and score is 7. Which arrow do you follow?

A The No arrow

B The Yes arrow

4. A flowchart sets count to 0, then has a box 'Add 1 to count'. After the box runs once, what is count?

A 1

B 0

5. Why do you write down the counter each time it changes?

A So you can skip the diamonds

B So you answer each diamond with the current value

Match the Pairs

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

Left column		Right column
1Oval labelled Start		AOval labelled End
2Diamond: Is count = 3?		Bcount: 0 → 1 → 2 → 3
3Write down each change to the counter so you can answer later diamonds correctly		CYou forgot to record the counter change, so later diamonds are answered with an old value.
4The result is found when your finger reaches the end oval		DA decision. Check the current value of count, then follow the Yes arrow or the No arrow.
5Count is 2. The diamond asks 'Is count = 5?' and you follow the Yes arrow.		EThis is where you put your finger first. Begin here and follow the arrow out of it.
6A loop adds 1 to count each time, but you skip writing the new value and keep using 0.		FThe answer to the diamond is wrong. 2 is not 5, so you must follow the No arrow.

Definitions

trace a flowchart

Fill in the Blanks

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

_____ count ← 0 IF count < 3 THEN

Diamond: is count less than 5? IF count _ 5 THEN

count ← 3 count ← count _ 1 Now count is 4

count ← 0 ______ 3 TIMES count ← count + 1

count ← count + 1 SAY count ___

Spot the Error

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

Question 1

A START

B count <- count + 1

C REPEAT 3 TIMES

D count <- count + 1

E SHOW count

Question 2

A START

B INPUT mark

C IF mark >= 50 THEN

D SHOW "Try again"

E ELSE

F SHOW "Try again"

Question 3

A END

B score <- 0

C score <- score + 2

D SHOW score

E END

Question 4

A START

B lives <- 0

C REPEAT UNTIL lives = 0

D lives <- lives - 1

E SHOW lives

Question 5

A SHOW age

B IF age >= 10 THEN

C SHOW "Big kid"

D ELSE

E SHOW "Little kid"

Answer Key

Following a flowchart to predict the result

Section A: Quick Questions

B — At the Start oval

A — Follow the arrows

A — The No arrow

A — 1

B — So you answer each diamond with the current value

Section B: Match the Pairs

Oval labelled Start → This is where you put your finger first. Begin here and follow the arrow out of it.

Diamond: Is count = 3? → A decision. Check the current value of count, then follow the Yes arrow or the No arrow.

Write down each change to the counter so you can answer later diamonds correctly → count: 0 → 1 → 2 → 3

The result is found when your finger reaches the end oval → Oval labelled End

Count is 2. The diamond asks 'Is count = 5?' and you follow the Yes arrow. → The answer to the diamond is wrong. 2 is not 5, so you must follow the No arrow.

A loop adds 1 to count each time, but you skip writing the new value and keep using 0. → You forgot to record the counter change, so later diamonds are answered with an old value.

Section C: Definitions

trace a flowchart — Start at the oval, follow each arrow with your finger, answer every diamond using the current values, write down counter changes, and stop at the end oval to find the result.

Section D: Fill in the Blanks

START
count ← 0
IF count < 3 THEN

Diamond: is count less than 5?
IF count < 5 THEN

count ← 3
count ← count + 1
Now count is 4

count ← 0
REPEAT 3 TIMES
  count ← count + 1

count ← count + 1
SAY count
END

Section E: Spot the Error

B — The counter needs a starting value before the loop. count + 1 can't be worked out if count has no value yet. It should be count <- 0.

D — This is the YES arrow of the diamond. When mark >= 50 is true you follow it, so it should show "Pass". "Try again" belongs on the ELSE (NO) path.

A — A flowchart begins at the START oval, so you know where to put your finger first. Line 1 should be START. END is where you stop.

B — The starting value should be 3. If lives starts at 0, the loop condition is already true and the loop never runs. Lives needs to count down from 3 to 0.

A — The diamond needs a value for age to answer its question. The first step should be INPUT age so the value is entered, not shown.