A pie chart shows how a whole is shared. When the circle is split into equal parts, count the parts in a sector and write them over the total number of parts: 3 of 8 parts is 3/8. For a percentage, the whole is 100%, so each part is 100% ÷ the number of parts. To find how many people chose something, share the total number of people into the parts, then take as many parts as the sector covers.
Explore this idea with maths tools
Maths you can move
Build 8 + 5
Tap two gold counters to fill the ten-frame.
8 in the frame + 5 waiting. The total stays the same.
Words to know
- sector
- one slice of the pie chart
- whole
- the full circle, which stands for everyone in the survey
- percentage
- an amount out of 100
Worked examples
The circle has 8 equal parts and Pasta covers 3. What fraction chose Pasta?
- 1.Count the parts in the sector: 3.
- 2.3 out of 8 parts is 3/8.
= 3/8
The circle has 20 equal parts and Beach covers 7. What percentage chose Beach?
- 1.Each part is 100% ÷ 20 = 5%.
- 2.7 × 5% = 35%.
= 35
40 people; the circle has 10 equal parts and Soccer covers 3. How many chose Soccer?
- 1.One part is 40 ÷ 10 = 4 people.
- 2.3 × 4 = 12.
= 12
For parents
Method: Count the equal parts
What to say: How many equal parts is the whole circle? How many does this sector cover?
Common mistakes:
- Gives the rest of the circle instead of the sector asked about.
- Compares the sector with the rest instead of with the whole circle.
- Treats every sector as the same size, so each choice gets an equal share.
- Gives the number of parts as the percentage or count.
- Gives the percentage of the circle as the number of people.
- Counts every part as 10% whatever the number of parts.