All skills › Year 7 › Multiplication
Year 7 · Multiplication
Prime factorisation
A prime number has exactly two factors: 1 and itself. Composite numbers have more.
How to do it
- Try dividing by 2, 3, 5, 7… up to its square root.
- If nothing divides it, it is prime.
- Prime factorisation: keep dividing by the smallest prime.
Worked example
Write 52 as a product of prime factors.
Divide by the smallest prime again and again: 52 = 2 × 2 × 13.
Answer: 2 × 2 × 13
With a free account, these play as step-by-step animations.
Watch out1 is not prime. 2 is the only even prime.
Practise Prime factorisation properly
Ten-question rounds with instant marking, a lesson under every question, stars and badges. Free to start, and the first week includes Premium.
Create a free account
More Multiplication skills