Divided 15 by 5 to get 3 but stopped there, forgetting to multiply by 3. Finding 1/5 of 15 is only the first step — the answer is 3/5, so multiply 3 by 3.
PRIMARY 2 · MATHEMATICS
Volume of Liquid
Top 5 mistakes
Ranked by how often they appear across 23 MOE-aligned practice questions in our archive.
Found 1/5 of 15 correctly (15 ÷ 5 = 3), then multiplied by 2 instead of 3, giving 6. The numerator of the fraction is 3, not 2.
Subtracted 3 from 15 to get 12, thinking '3/5 full' means '3 litres less than full'. The fraction 3/5 means 3 out of every 5 equal parts, not 3 litres subtracted.
Mass of a teaspoon — too little for a pail.
Half a litre — a drink bottle, not a pail.
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