Prime Factorisation

Ages 10–14

Difficulty adapts to you

Prime Factorisation

Every whole number greater than 1 can be written as a product of prime numbers. Apart from the order of the factors, that prime factorisation is unique.

Your goals

✓You can break numbers down into their prime factors.
✓You can use prime factor, prime factorisation correctly.
✓You can multiply all prime factors to recover the original number.

Words to know

prime factor:: A factor that is also a prime number.
prime factorisation:: A whole number greater than 1 written as a product of prime factors.

Examples

112 = 2 × 2 × 3 = 2² × 3.
260 = 2 × 2 × 3 × 5 = 2² × 3 × 5.

Check these

• Do not leave a composite number in the final factorisation.
• Keep every number, symbol, label, and unit in its correct place.
• Show enough working to check how you reached your answer.

Helpful habits

• Read the whole question before choosing what to do.
• Show one clear step at a time and check each step.
• If you are stuck, draw a model, try smaller numbers, or revisit the example.

Now try your own

Create your own prime factorisation example, solve it, and explain how you checked it.

Professor Wise Owl

Wisdom & Understanding

“Every expert was once a beginner. You are on your way!”