Factors of a Number

Factors

The factors of a number are the numbers that will divide into that number and

leave no remainder. This, of course, includes 1 and the number you’re

interested in - which happen to be the numbers you start with when working

out factors of a number.

How to...

Find the factors of 90

1. Make a list starting with ‘1 times 90’.

2. Find the next number that will divide exactly into 90 and write it as your

second ‘list item’ (‘2 x 45’).

3. Continue but stop when your numbers begin to repeat. (Below, the next

item after ‘9 x 10’ would be ’10 x 9’ - a repeat!

4. Write down the numbers in order from smallest to largest. Here I’ve just

gone down the left and up the right, following the direction of the red

arrows, to ensure all the numbers are in ascending order.

5. To check, each row’s numbers, when multiplied together, should give 90

as the product.

The factors of 90 are:

1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90