The term ‘prime factor’ is one which would make many adults shudder as they try to think back to their school days. In fact, it is a term that children would probably not met until secondary school, but is now firmly incorporated into the primary curriculum.

Here we have a maths worksheet for year 6 on how to find prime factors. Before attempting this page it is necessary for children to have a good understanding of what factors are and what prime numbers are.

One of the easiest ways of finding prime factors is to use a diagram, rather like a tree diagram with the numbers at the bottom all being the prime factors. Frequently the same number is found more than once. For example the prime factors of 36 are 3, 3, 2 and 2.

Starting with the number itself, find two numbers which multiply together to make that number. For example 36 can be made by multiplying 18 by 2. 18 and 2 are both factors of 36. Repeat this process until only prime numbers are left.

A good way of checking if all the factors have been found is to multiply them and the original number should result. e.g. 3 x 3 x 2 x 2 = 36

This page is found in our Year 6 calculating section .