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Factors of a Number





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
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