Primary 4 Maths: Pie Charts
Reading and interpreting pie charts as simple fractions of a whole, and solving problems from them — worked examples for the P4 Maths syllabus.
Most schools typically cover this topic in Term 4, around weeks 4–5 — though every school sets its own sequence.
Pie charts moved down to Primary 4 under the 2021 MOE Mathematics syllabus — two years earlier than under the previous syllabus, when they were taught at P6. The P4 scope stays deliberately simple: reading a pie chart, interpreting what each slice represents, and solving problems where every slice is labelled as a simple fraction of the whole — halves, quarters, thirds, eighths. Percentage isn't taught until P5, so a P4 pie chart question never asks for "what percentage" — only "what fraction" or "how many", once the total is known.
The one new idea a pie chart adds on top of fraction skills your child already has is this: all the slices' fractions add up to make one whole pie. That single fact does almost all the work — if a chart shows three slices and only two fractions are labelled, the third is always "1 whole minus the other two," which is P4 fraction subtraction wearing a different picture. Once that's automatic, pie chart questions become fraction-of-a-set questions with an unusually clear diagram attached.
P4 Pie Charts: the mistakes to watch for
- Judging a slice's fraction by its angle at the centre "look" rather than its label. Pie charts in exam questions are not always drawn precisely to scale — the fraction given in words or in the legend is what's correct, not a protractor reading of the printed picture.
- Forgetting that all the slices must add up to a whole. A chart with only some fractions labelled always has the rest sitting in "1 − the fractions given" — the most common way P4 pie chart questions hide their real subtraction step.
- Mixing up "the fraction of the pie" with "the number of items". A slice can be 1/4 of a pie chart and still represent a completely different number of items depending on the total — the fraction has to be multiplied by the total before it becomes an actual quantity.
- Comparing slices without a common denominator. "Which is bigger, 1/3 or 3/8?" can't be answered by comparing the top numbers alone; convert to a common denominator first, exactly as in ordinary fraction comparison.
P4 Pie Charts: reading the whole and its slices
P4 Pie Charts: easy warm-ups
Easy: reading a labelled slice
A pie chart shows how 40 pupils voted for their favourite drink. The "Milk" slice is labelled 1/2. How many pupils chose milk?
Show the worked solution
1/2 of 40 = 40 ÷ 2 = 20 pupils.
Easy: a smaller slice
Using the same pie chart of 40 pupils, the "Water" slice is labelled 1/8. How many pupils chose water?
Show the worked solution
1/8 of 40 = 40 ÷ 8 = 5 pupils.
Easy: the missing slice
A pie chart of a garden's flowers has three slices: roses are 1/2 of the chart, tulips are 1/4. What fraction of the chart is the remaining slice, daisies?
Show the worked solution
Roses and tulips together = 1/2 + 1/4 = 2/4 + 1/4 = 3/4.
Daisies = 1 − 3/4 = 1/4.
Easy: comparing two slices
In a pie chart, the "cats" slice is 1/3 and the "dogs" slice is 1/6. Which pet is more popular?
Show the worked solution
Convert to the same denominator: 1/3 = 2/6.
2/6 is greater than 1/6, so cats are more popular.
P4 Pie Charts: exam-style questions
Exam: finding a total from one slice
A pie chart shows the sweets in a jar. The "green" slice is 1/2 of the chart and represents 12 sweets. How many sweets are in the jar altogether?
Show the worked solution
1/2 of the total = 12, so the total = 12 × 2 = 24 sweets.
Exam: the third slice by subtraction
A pie chart of 24 sweets has three slices: red is 1/3, green is 1/2, and the rest are blue. How many sweets are blue?
Show the worked solution
Fraction blue = 1 − 1/3 − 1/2. Convert to sixths: 1 = 6/6, 1/3 = 2/6, 1/2 = 3/6.
Blue = 6/6 − 2/6 − 3/6 = 1/6.
Number of blue sweets = 1/6 × 24 = 4 sweets.
Exam: comparing two quantities from one chart
Using the same 24-sweet chart (red 1/3, green 1/2, blue 1/6), how many more green sweets are there than red sweets?
Show the worked solution
Red = 1/3 × 24 = 8 sweets. Green = 1/2 × 24 = 12 sweets.
Difference = 12 − 8 = 4 more green sweets.
Exam: a pie chart with four slices
A pie chart of 40 pupils' favourite drink shows milk 1/2, juice 1/4, water 1/8 and soya bean milk 1/8. How many pupils chose either juice or soya bean milk?
Show the worked solution
Juice = 1/4 × 40 = 10 pupils. Soya bean milk = 1/8 × 40 = 5 pupils.
Juice or soya bean milk = 10 + 5 = 15 pupils.
Exam: working backwards from a difference
A pie chart splits a class into two slices: those who walk to school and those who don't. The "walk" slice is 3/8 of the class. If 15 pupils walk to school, how many pupils are in the class altogether?
Show the worked solution
3/8 of the class = 15 pupils, so 1/8 of the class = 15 ÷ 3 = 5 pupils.
Whole class = 8/8 = 8 × 5 = 40 pupils.
P4 Pie Charts: PSLE-challenge preview
PSLE challenge: two slices given, one difference found
A pie chart of 48 storybooks in a class library shows fiction as 5/8 of the collection and non-fiction as the rest. How many more fiction books are there than non-fiction books?
Show the worked solution
Fiction = 5/8 × 48 = 30 books. Non-fiction fraction = 1 − 5/8 = 3/8, so non-fiction = 3/8 × 48 = 18 books.
Difference = 30 − 18 = 12 more fiction books.
Check: 30 + 18 = 48, the full collection. ✓
PSLE challenge: a slice split further
A pie chart of 60 pupils shows that 1/3 of the pupils cycle to school. Of the pupils who cycle, 1/4 of them cycle with a friend. How many pupils cycle with a friend?
Show the worked solution
Pupils who cycle = 1/3 × 60 = 20 pupils.
Of those, cycling with a friend = 1/4 × 20 = 5 pupils.
PSLE challenge: three slices, one total unknown twice over
A pie chart of a fruit stall's morning sales has three slices: apples 1/4, oranges 1/3, and pears making up the rest. If the stall sold 50 more oranges than apples, how many pears were sold?
Show the worked solution
Oranges − apples in fraction = 1/3 − 1/4. Convert to twelfths: 1/3 = 4/12, 1/4 = 3/12, so the difference is 1/12.
1/12 of the total = 50, so the total = 50 × 12 = 600 fruits.
Pears' fraction = 1 − 1/4 − 1/3 = 12/12 − 3/12 − 4/12 = 5/12.
Pears sold = 5/12 × 600 = 250 pears.
Check: apples 150, oranges 200, pears 250; 200 − 150 = 50, and 150 + 200 + 250 = 600. ✓
P4 Pie Charts: how to practise this topic
Because a P4 pie chart is really a fraction-of-a-whole question with a circle drawn around it, the most useful practice isn't more charts — it's fluency with fraction basics: finding a common denominator, taking a fraction of a quantity, and working "1 minus the given fractions" without hesitating. A child who's solid there will find pie charts one of the more comfortable topics on this list, not a new thing to learn from scratch.
What this topic covers
In the MOE Primary Mathematics syllabus, Primary 4 Pie Charts includes the concepts below. (P4-M-12 is Test Paper's own topic code, not an MOE reference.)
- Reading pie charts
- Interpreting pie charts
- Solving problems using pie charts
- Pie charts with fractions
Where to go next
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