Singapore Math Drills Team · 12 June 2026
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Here is something every Primary 5 and 6 parent should know: in PSLE Paper 2, your child can get a wrong final answer and still earn marks. Not out of charity — because the marking scheme explicitly awards method marks for correct working even when arithmetic slips at the last step.
This matters enormously for exam performance. A child who gets the method right but makes a small arithmetic error in a 4-mark question might salvage 2 or 3 of those marks — if they showed their working clearly. A child who works it out correctly in their head, writes only the answer, and then makes an error earns zero.
"Show your working" is not a vague instruction. It's a transferable skill that can be taught and practised. Here's how.
In Paper 2 word problems, marks are awarded at two levels:
A typical 4-mark Paper 2 question might have 2 method marks and 2 answer marks. A student who draws the correct bar model, writes the correct equations, but makes a multiplication slip at the last step earns 2 of the 4 marks. A student who writes only a single incorrect number earns zero — even if their reasoning was sound.
This is not a quirk of PSLE. It reflects the deeper goal of Singapore Mathematics education: the ability to reason through a problem matters as much as arriving at the correct number.
Question (P5 difficulty): A tank holds 240 litres when full. It is currently ¾ full. After 30 litres are removed, what fraction of the tank is still filled?
Poor working (common mistake):
Student writes: 240 × ¾ = 180. 180 – 30 = 150. 150/240.
This is actually correct — but there's no structure. If the student had written 180 instead of 150 (a common subtraction slip), the examiner cannot award method marks because no method is visible.
Clear working:
Full capacity = 240 litres
Current amount = ¾ × 240 = 180 litres
After removal = 180 – 30 = 150 litres
Fraction remaining = 150/240 = 5/8
The second version shows each step explicitly. If the student wrote 160 instead of 150, the examiner can see that the method through step 3 was correct and award partial marks.
The difference between these two approaches is not mathematical ability — it's the habit of externalising reasoning.
There are a few common reasons children avoid writing their working:
Speed habit from Paper 1. Paper 1 is multiple-choice and short-answer. Working is rarely required there, and children practise it for years before Paper 2. The habit of computing in the head and writing only the answer is deeply ingrained by the time Paper 2 matters.
Confidence in mental arithmetic. Children who are good at arithmetic often find written working unnecessary for easy questions — and that's correct. The problem is they apply the same approach to hard questions where mental arithmetic is unreliable.
Fear of showing an error. Some children avoid writing working because they don't want to be "wrong on paper." This is a confidence issue more than a technique issue, and it usually comes from a history of working being marked as "wrong" rather than partially correct.
The best way to build the working habit is to make it the default — not a special exam-day mode, but the normal way your child solves problems during daily practice.
This is harder than it sounds with a tablet or laptop, because typing equations doesn't feel natural and doesn't match the pencil-and-paper experience of the exam. Copy-pasting results in working that looks clean but wasn't worked through step by step.
Singapore Math Drills includes a built-in scratch pad — a full-screen digital canvas that overlays any question in the app. Your child can:
Crucially, the scratch pad is native to the app — your child doesn't switch to a separate tool or a paper notebook that's easy to skip. It's one tap away from any question, which means the friction of "I should probably write this down" disappears.
The scratch pad doesn't submit or check the working. It's a thinking space, not a marking tool. This means your child can cross things out, try different approaches, and abandon a line of working without penalty — exactly the behaviour you want to encourage.
A few practical approaches that work for primary-age children:
Narrate first, write second. Ask your child to say out loud what they're going to do before they write anything. "I'm going to find ¾ of 240 first, then subtract 30." Once they've said it, write each step as they say it.
One thought, one line. A simple rule: every new piece of reasoning goes on its own line. Resist the urge to compress two steps into one expression until the method is automatic.
Check working before the answer. Before asking "what did you get?", ask "can you show me how you set it up?" The answer is almost always findable from correct working — but correct working can't be produced from a wrong answer.
Reward method, not outcome. If your child sets up a problem correctly but makes an arithmetic slip, acknowledge the correct method explicitly: "You set that up perfectly — let's just re-check the multiplication." This builds the sense that the process has value independent of the number at the end.
The free sample drills on Singapore Math Drills include the scratch pad — try it on a Paper 2 style word problem and practice showing your working before checking the answer.
Try a free sample drill with the scratch pad →
No account required. The scratch pad is available on every question in the sample.