Factors, multiples and primes describe how numbers are built. A multiple is in a number’s times table; a factor divides into it exactly; a prime has no factors except 1 and itself.
What your child will learn
- Find factors and multiples of a number
- Recognise prime numbers up to 50
- Know the square numbers up to 12 × 12
- Find the lowest common multiple of two numbers
Factors go in, multiples come out
The factors of 12 are 1, 2, 3, 4, 6 and 12 — they all divide into 12. The multiples of 12 are 12, 24, 36… — the 12 times table. A prime number such as 13 has exactly two factors. The number 1 is not prime, because it has only one.
Example questions
Here are a few questions like the ones in the first quest. Can you solve them?
1. Which of these is a multiple of 8?
- 48
- 46
- 55
- 49
Show answer
Answer: 48. 8 × 6 = 48, so 48 is in the 8 times table.
2. Which of these is a factor of 56?
- 18
- 6
- 19
- 2
Show answer
Answer: 2. 56 ÷ 2 = 28 exactly, so 2 is a factor of 56.
3. Which of these is a multiple of 3?
- 32
- 31
- 30
- 29
Show answer
Answer: 30. 3 × 10 = 30, so 30 is in the 3 times table.
Tips for grown-ups
- Arrange 24 counters into as many different rectangles as you can: each one shows a pair of factors.
- Circle the primes on a hundred square and look for patterns.