This can be best understood by an illustrative example.

If two numbers are multiplied, then these are called the factor pairs of the new number. For Example, if 3 is multiplied with 5, the result is 15. Then 3 and 5 are the factor pairs of 15. Having understood the meaning of factor pair, we can now proceed to find the factor pairs of a given Number.

Let’s take for example a number 18. The first thing to do is to find out the numbers which can divide 18. Starting with 1, this can be divided by 2,3,6,9 and 18. These are the factors of 18. Hence first of all factorise the given number. Next we can choose pairs out of 1,2,3,6,9,18 so that the product is 18. Thus

1x18= 18 = 18x1

2x9=18 = 9x2

3x6=18 = 6x3

The factor pairs of 18 are thus 1and 18, 2 and 9, 3 and 6

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