What are the missing numbers in the blanks? The number 6 is a factor of ______ and ______.
- 3, 4
- 6, 20
- 24, 36
- 12, 40
Need a hint?
A factor of a number divides it exactly. Try dividing each number in the options by 6 and see which pair has no remainder for both numbers.
Worked answer
- A factor of a number divides it exactly, with no remainder.
- 6 must divide both numbers exactly.
- 24 ÷ 6 = 4 and 36 ÷ 6 = 6, so 6 divides both exactly.
- In every other pair, at least one number leaves a remainder when divided by 6 (3, 4, 20 and 40).
- Answer: 24, 36.
Answer: 24, 36
The mistake this question tests
Habit
Factors and multiples (HCF, LCM)
Pupils often pick 12, 40 because 12 ÷ 6 = 2, but forget to check that 40 ÷ 6 leaves a remainder of 4.
How to fix it at home →Wrong answers children often give:
- 12, 40 Factors and multiples (HCF, LCM)
- 3, 4 Factors and multiples (HCF, LCM)
- 6, 20 Factors and multiples (HCF, LCM)
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See the answer →Practise PSLE whole numbers until the mistakes stop.
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