PSLE whole numbers questions with worked answers
Whole numbers look like the easy marks, so a slip here hurts more than anywhere else. Your child needs to read large numbers, follow the order of operations without a calculator, and tell a common factor from a common multiple when a problem sum hides which one it wants.
What the PSLE tests in whole numbers
- Reading, writing and comparing numbers up to 10 million, and the value of each digit
- Rounding to the nearest 10, 100, 1000 and estimating answers
- The four operations, including multiplying and dividing by 10, 100, 1000 and their multiples
- Order of operations with brackets, worked without a calculator in Paper 1
- Factors, multiples, common factors and common multiples in problem sums
Where children lose the most marks
- Problem sums that need a common factor (sharing into equal groups) or a common multiple (things that repeat), without saying which
- Long expressions with brackets where one step done out of order changes the answer
- Multi-step money and quantity problems in Paper 2 where the working is marked, not only the answer
A PSLE-style question, worked
Mei has 84 red beads and 60 blue beads. She packs all of them into identical bags so that every bag has the same number of red beads and the same number of blue beads, with none left over. What is the greatest number of bags she can pack?
- Factors of 84: 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84
- Factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
- Highest common factor of 84 and 60 = 12
- Check: 84 ÷ 12 = 7 red beads and 60 ÷ 12 = 5 blue beads in each bag
Why 420 bags is wrong: The child found the lowest common multiple of 84 and 60 instead of the highest common factor. Sharing into equal groups always needs a common factor, and 420 bags is more bags than there are beads.
Free PSLE whole numbers questions with answers
Careless mistakes to watch in whole numbers
Factors and multiples (HCF, LCM)
Your child uses the HCF when the question needs the LCM, or the other way round. How to tell them apart in PSLE word problems and fix the habit.
See the fix →Calculation slip
Your child uses the right method but slips on the arithmetic, like a missing zero in long division. How to spot calculation slips and cut them down.
See the fix →Questions parents ask
Is a calculator allowed for whole numbers questions in the PSLE?
Only in Paper 2. Paper 1 is done without a calculator, so your child must be able to multiply, divide and follow the order of operations by hand.
Do PSLE questions still test factors and multiples in P6?
Yes. Factors and multiples are taught in earlier years but commonly appear in PSLE problem sums, usually about sharing items equally or events that repeat.
How can my child stop losing marks on easy whole numbers questions?
Most lost marks here are slips, not gaps in understanding. Knowbotic traces every wrong answer to the habit behind it and has your child practise that habit until they get 3 right in a row.
See which habits are costing your child marks.
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