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• For example: The factors of 20 can be found by considering pairs of numbers that multiply to give 20 which are 1 × 20, 2 × 10 and 4 × 5 Therefore, written in ascending order, the factors of 20 are 1, 2, 4, 5, 10, 20

• Every whole number is a factor of itself and also 1 is a factor of every whole number.

■ Multiples of a particular number are numbers created by multiplying the particular number by any whole number.

• For example: The multiples of 20 are 20, 40, 60, 80, 100, 120, …

Other numbers that are multiples of 20 include 480, 2000 and 68 600. There is an infinite number of multiples!

■ Given the statements above, it follows that factors are less than or equal to the particular number being considered and multiples are greater than or equal to the number being considered.

Building Understanding

1 For each of the following numbers, state whether they are factors (F), multiples (M) or neither (N) of the number 60.

120 b 14

5

15

240

40

22

600

70

2 For each of the following numbers, state whether they are factors (F), multiples (M) or neither of the number 26.

54

27

Example 1 Finding factors

Find the complete set of factors for each of these numbers.

Now you try

Find the complete set of factors for each of these numbers.