Multiples and Factors, Study notes of Elementary Mathematics

Download Multiples and Factors and more Study notes Elementary Mathematics in PDF only on Docsity!

Multiples and Factors

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.

What are the first five multiples of 13?

• 13 x 1 =
• 13 x 2 =
• 13 x 3 =
• 13 x 4 =
• 13 x 5 =
  • 13, 26, 39, 52,

Find the Missing Multiples

• 6, 12, 18, ____, ____
• ___, 6, 9, 12, ____, ____, 21
• ___, 24, 36, 48, 60, ____

Finding Factors

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

What are the factors of 7?

1 x 7

2 x ??

3 x ??

4 x ??

5 x ??

6 x ??

7 x 1 This works, but it is a repeat. Weare done.

The only factors

of 7 are 1,

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