Primary 5 Maths: Fractions
Why P5 Fractions is the hardest jump in upper primary Maths, the mistakes most children make, and worked examples of the question types that appear in year-end exams.
Most schools typically cover this topic in Term 1, around weeks 2–5 — though every school sets its own sequence.
Ask any upper primary Maths teacher which P5 topic separates confident students from struggling ones, and the answer is almost always the same: fractions. In Primary 5, fractions stop being about shading parts of a circle. Your child now adds and subtracts unlike fractions, multiplies and divides fractions, works with mixed numbers, and — the real test — solves multi-step fraction word problems where the fraction refers to a remainder, not the whole.
This topic feeds directly into P6 Fractions, Ratio, and Percentage. A gap here doesn't stay here; it compounds.
The mistakes to watch for
- Adding denominators. Under time pressure, 1/3 + 1/4 becomes 2/7. Your child knows the rule; the error appears when working speed matters. That's a fluency gap, not a knowledge gap — and it shows up in Paper 1, where no calculator is allowed.
- "Of the remainder" read as "of the whole". In word problems, "She gave away 1/4 of her stickers, then 2/5 of the remainder…" trips more P5 students than any other phrasing. If your child multiplies 2/5 by the original amount, they've missed the remainder concept.
- Division upside down. 3/4 ÷ 6 answered as 8 instead of 1/8 — flipping the wrong number. The fix is understanding why dividing by 6 makes a piece smaller, not memorising "keep-change-flip".
- Mixed numbers left unconverted. Multiplying 2 1/2 × 3/5 without converting to 5/2 first.
Example question — remainder concept
Try it: fraction of a remainder
Mrs Lim baked some muffins. She gave 1/4 of them to her neighbour and 2/5 of the remainder to her sister. She had 27 muffins left. How many muffins did she bake?
Show the worked solution
After giving 1/4 away, the remainder is 3/4 of the muffins.
Her sister received 2/5 of that remainder, so 3/5 of the remainder was left:
3/5 × 3/4 = 9/20 of all the muffins = 27 muffins left.
So 9/20 of the muffins is 27, meaning 1/20 is 27 ÷ 9 = 3, and the whole batch = 20 × 3 = 60 muffins.
Check: 60 → neighbour gets 15, remainder 45 → sister gets 18 → 27 left. ✓
Try it: dividing a fraction by a whole number
A 3/4-litre bottle of juice is poured equally into 6 cups. How much juice is in each cup?
Show the worked solution
3/4 ÷ 6 means splitting 3/4 into 6 equal parts.
3/4 ÷ 6 = 3/4 × 1/6 = 3/24 = 1/8 litre in each cup.
Sense check: each cup must hold much less than the whole 3/4 litre — 1/8 is reasonable; 8 litres would not be.
How to practise this topic
Fraction skills fade quickly if they're not revisited — a child who could add unlike fractions in March may fumble them by August. Two things matter: practising the remainder structure until the bar model is automatic, and coming back to the topic after a gap to check it stuck. A short focused set every few days beats one long weekend session.
What this topic covers
In the MOE syllabus, Primary 5 Fractions (P5-M-02) includes:
- Addition of unlike fractions
- Subtraction of unlike fractions
- Multiplication of fractions
- Division of fractions
- Operations on mixed numbers
- Converting between mixed numbers and improper fractions
- Fraction of a set of items
- Fraction word problems
Before this topic
These topics feed into Fractions — if this one wobbles, check them first: Primary 4 Fractions.
Is Fractions actually solid?
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