How to Find Factors

Finding Factors

The factors of a number can be found.

A Simple Example of How to Find Factors

Finding the factors of a number is easy.

Find pairs of numbers that multiply to make that number.

Question

What are the factors of the number 18?

Step-by-Step:

1

1 and the number itself (18) are factors of 18.

1 × 18 = 18

Write 1 and 18 on the outside of a grid.

1 and 18 on the outside of a grid

2

Divide 18 by 2. Does it divide exactly?

18 ÷ 2 = 9

Yes.

2 and the answer of the division (9) are factors of 18.

2 × 9 = 18

Write 2 and 9 in the grid, just inside the outside entries.

2 and 9 on the outside of a grid

3

Divide 18 by 3. Does it divide exactly?

18 ÷ 3 = 6

Yes.

3 and the answer of the division (6) are factors of 18.

3 × 6 = 18

Write 3 and 6 in the grid, just inside the previous entries.

3 and 6 on the outside of a grid

4

Divide 18 by 4. Does it divide exactly?

18 ÷ 4 = 4.5

No. The answer is not a whole number. 4 is not a factor.

5

Divide 18 by 5. Does it divide exactly?

18 ÷ 5 = 3.6

No. The answer is not a whole number. 5 is not a factor.

6

Divide 18 by 6.

We already know that 6 is a factor of 18, it is already in the grid.

We have found all the factors.

Answer:

The factors of 18 are 1, 2, 3, 6, 9 and 18.

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See Also

What is a factor?