Since you can't divide 5 evenly into 36, 5 isn't a factor. Note that the same is true of 7 and 8. Now you've determined all the factors of 36 using some basic division.

There are many methods to find the prime factors of a number, but one of the most common is to use a prime factor tree. Firstly, find two numbers that will multiply together to give 40. These are ...

Learn how to work out the factors of a number using a diagrammatic representation and factor trees in this KS3 maths study guide from BBC Bitesize.

Then, follow the prime factorization steps outlined in the previous section. The procedure is the same, except you write each of the factor pairs underneath the previous numbers.