Common Factors and Greatest Common Factors

1
Common Factors and Greatest Common Factors

• How to find them and what to do with them!

2
What are factors?

• The numbers you multiply together to get a
  product.
• Example 8 X 3 24 So 8 and 3 are factors of
  24.
• What are some other factors?

3
What are the factors of 24

• 1 X 24
• 2 X 12
• 3 X 8
• 4 X 6

4
When we talk about fractions we will need to find
common factors.

• Then you will need to look at the list and
  determine the factors they have in common

• You will need to make a list of all the factors
  of both numbers

5
What are the common factors of

• 24 and 36
• List all the factors for both numbers

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24 and 36

• FACTORS OF 24
• 1 X 24
• 2 X 12
• 3 X 8
• 4 X 6

• FACTORS OF 36
• 1 X 36
• 2 X 18
• 3 X 12
• 4 X 9
• 6 X 6

7
Which factors do they have in common

• The factors of 24 are 1,2,3,4,6,8,12,24
• The factors of 36 are 1,2,3,4,6,9,12,18,36
• They have 1,2,3,4,6, and 12 in common.
• What is the greatest common factor?

8
The Greatest Common Factor

• (also known as the GCF)
• is 12

9
Try some more!

• What is the Greatest Common Factor of 6 and 30?
• What is the GCF of 14 and 20?
• What is the GCF of 4 and 8?

10
Some questions to think about

• Can one of the numbers be the Greatest Common
  Factor? If so, when?
• Is it possible to have 1 as a Greatest Common
  Factor? If so, when?