Factors and Multiples

Multiples

• A multiple is formed by multiplying a

given number by the counting numbers.

• The counting numbers are 1, 2, 3, 4, 5,

6, etc.

Example: List the multiples of 4:

• 4 x 1 = 4
• 4 x 2 = 8
• 4 x 3 = 12
• 4 x 4 = 16
• 4 x 5 = 20
• 4 x 6 = 24

Counting Numbers

So, the multiples of 4
are 4, 8, 12, 16, 20, 24,
28, etc.

What are the first five

multiples of 13?

13 x 1 =13

13 x 2 = 26

13 x 3 = 39

13 x 4 = 52

13 x 5 = 65

13, 26, 39, 52, 65

Find the Missing Multiples

• 6, 12, 18, ____, ____

• ___, 6, 9, 12, ____, ____, 21

• ___, 24, 36, 48, 60, ____

Find the Missing Multiples

• 6, 12, 18, ____, ____

• ___, 24, 36, 48, 60, ____

24

30

12

72

• ___, 6, 9, 12, ____, ____, 21

3

15 18

Factors

• Factors are the numbers you multiply

together to get a product.

• For example, the product 24 has several

factors.

• 24 = 1 x 24
• 24 = 2 x 12
• 24 = 3 x 8
• 24 = 4 x 6
• SO, the factors are 1, 2, 3, 4, 6, 8, 12, 24

Finding Factors

• Start with 1 x the number.
• Try 2, 3, 4, etc.
• When you repeat your factors, cross out.

**When the factors repeat - you’re done at this point.

• If you get doubles (such as 4 x 4), then

you’re done. Repeats or doubles let
you know you’re done.

What are the factors of 16?

1 x 16
2 x 8
3 x ??
3 is not a factor, so cross it out

4 x 4
doubles = done

The factors of 16 are
1,2,4,8,16

What are the factors of 18?

1 x 18
2 x 9
3 x 6
4 x ??

5 x ??
6 x 3

Repeat! Cross it out!
We’re done!

The factors are
1,2,3,6,9,18

Prime and Composite

Numbers

Prime numbers are
numbers that only have
two factors: one, and the
number itself.

EXAMPLES:
3, 5, 7, 11, 31

Composite numbers
have more than two
factors.

EXAMPLES:
6, 18, 30, 100