Primary 4 Maths: Fractions
Primary 4 is where fraction understanding is built: mixed numbers, equivalent fractions, adding related fractions. Get this right and P5 gets easier.
Most schools typically cover this topic in Term 2, around weeks 1–4 — though every school sets its own sequence.
Primary 4 fractions is a foundation topic in the truest sense: everything your child does with fractions in P5 and P6 — and most of what they do with ratio and percentage — stands on what's built this year. The P4 scope is friendly: understanding mixed numbers and improper fractions, finding equivalent fractions, comparing fractions, and adding and subtracting related fractions (where one denominator divides the other, like thirds and sixths).
The single most important idea of the year is equivalence — that 2/8 and 1/4 are the same number wearing different clothes. Children who truly own equivalence find P5's unlike-fraction arithmetic a small step. Children who memorised their way past it hit a wall next year.
P4 Fractions: the mistakes to watch for
- Fractions treated as two separate whole numbers. Comparing 3/8 and 3/5 by declaring 8 "bigger". The fraction is one number, not a pair — and 3/5 is the larger here because fifths are bigger pieces than eighths.
- Equivalent fractions by adding. Turning 1/4 into 2/5 by adding 1 to top and bottom. Equivalence multiplies; it never adds.
- Mixed-number conversion slips. 2 3/8 should become 19/8 (2 × 8 + 3). A wrong conversion poisons every later step, so this needs to be fast and checked.
- Adding related fractions without converting first. 1/4 + 3/8 — a related-fraction pair, since 4 divides into 8 — attempted as 4/12 instead of converting to 2/8 + 3/8 = 5/8.
P4 Fractions: what equivalence looks like
P4 Fractions: easy warm-ups
Easy: converting a mixed number
Express 2 3/8 as an improper fraction.
Show the worked solution
Each whole is 8 eighths, so 2 wholes = 16 eighths.
16/8 + 3/8 = 19/8.
Check: 19 ÷ 8 = 2 remainder 3 → 2 3/8. ✓
Easy: converting an improper fraction
Express 17/5 as a mixed number.
Show the worked solution
15/5 = 3 wholes, with 2/5 left over.
17/5 = 3 2/5.
Check: 3 wholes = 15/5, plus 2/5 = 17/5. ✓
Easy: finding an equivalent fraction
Find the missing numerator: 2/3 = ?/12.
Show the worked solution
3 × 4 = 12, so multiply the numerator by 4 too.
2 × 4 = 8, so 2/3 = 8/12.
Easy: comparing two fractions
Which is greater, 5/6 or 3/4?
Show the worked solution
Convert both to twelfths: 5/6 = 10/12, and 3/4 = 9/12.
10/12 > 9/12, so 5/6 is greater.
P4 Fractions: exam-style questions
Exam: adding related fractions
Ali ate 1/4 of a pizza and his sister ate 3/8 of the same pizza. What fraction of the pizza was left?
Show the worked solution
Convert to the same denominator first: 1/4 = 2/8.
Eaten altogether: 2/8 + 3/8 = 5/8.
Left: 8/8 − 5/8 = 3/8 of the pizza.
Exam: mixed number in a measurement
A ribbon is 4 2/5 m long. Write this length as an improper fraction, in fifths.
Show the worked solution
4 wholes = 20 fifths, so 4 2/5 = 20/5 + 2/5 = 22/5.
Exam: ordering three fractions
Arrange 5/8, 3/4 and 1/2 in increasing order.
Show the worked solution
Convert to eighths: 1/2 = 4/8, 5/8 stays, 3/4 = 6/8.
In increasing order: 1/2, 5/8, 3/4.
Exam: checking equivalence
Sam says his rope is 3/5 of a metre long. Tom says his rope is 6/10 of a metre long. Are the two ropes the same length?
Show the worked solution
Multiply both parts of 3/5 by 2: 3/5 = 6/10.
Yes — 3/5 and 6/10 are equivalent fractions, so the ropes are the same length.
Exam: adding a distance in related fractions
Ali walked 2/3 km, then walked another 1/6 km. What was the total distance he walked?
Show the worked solution
Convert to sixths: 2/3 = 4/6.
4/6 + 1/6 = 5/6 km.
P4 Fractions: PSLE-challenge preview
PSLE challenge: subtracting mixed numbers
A wire of length 5 1/6 m is cut into two pieces. One piece is 2 5/6 m. What is the length of the other piece?
Show the worked solution
Convert to improper fractions: 5 1/6 = 31/6, and 2 5/6 = 17/6.
31/6 − 17/6 = 14/6 = 2 1/3 m.
Check: 2 1/3 + 2 5/6 = 2 2/6 + 2 5/6 = 4 7/6 = 5 1/6. ✓
PSLE challenge: two equivalent fractions at once
Find x and y such that 3/4 = 9/x = y/16.
Show the worked solution
3/4 = 9/x: since 3 × 3 = 9, multiply the denominator by 3 too: x = 4 × 3 = 12.
3/4 = y/16: since 4 × 4 = 16, multiply the numerator by 4 too: y = 3 × 4 = 12.
PSLE challenge: adding two mixed numbers
A baker used 2 1/3 kg of flour for bread and 1 5/6 kg of flour for a cake. How much flour did she use altogether?
Show the worked solution
Convert 2 1/3 to sixths: 2 1/3 = 2 2/6.
2 2/6 + 1 5/6 = 3 7/6 = 3 wholes + 1 whole + 1/6.
Total: 4 1/6 kg.
P4 Fractions: how to practise this topic
At P4, seeing fractions matters as much as computing them — fraction discs, bar diagrams, and number lines aren't babyish props, they're how equivalence becomes real. In practice sessions, mix comparison questions in with arithmetic so your child keeps reasoning about size, not just executing procedures. And check retention after a few weeks: equivalence that's still solid in the next school term is the best predictor that P5 fractions will go smoothly.
What this topic covers
In the MOE Primary Mathematics syllabus, Primary 4 Fractions includes the concepts below. (P4-M-04 is Test Paper's own topic code, not an MOE reference.)
- Equivalent fractions
- Mixed numbers
- Improper fractions
- Conversion between mixed numbers and improper fractions
- Comparing and ordering fractions
- Addition of unlike fractions
- Subtraction of unlike fractions
- Fraction of a set of objects
- Fraction word problems
Before this topic
These topics feed into Fractions — if this one wobbles, check them first: Primary 4 Factors & Multiples.
Where to go next
Is Fractions actually solid?
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