Greatest Common Factor

List the factors of 12 & 20, then identify the greatest common factor.
12-
20-
GCF=

• 12- 1, 2, 5, 7  20-10, 20, 30, 40 GCF 10

• 12-1, 12, 24, 36  20-20, 40, 60, 80 GCF 40

• 12-2, 4, 6   20-1, 10, 20 GCF 20

• 12-1, 2, 3, 4, 6, 12  20-1, 2, 4,5,10, 20 GCF 4

What is the greatest common factor of 10 and 25?

• 5

• 1

• 10

• ^₁

What is the GCF of 8 and 10?

• 1

• 3

• 4

• 2

Find the greatest common factor of 20 and 30

• 2

• 5

• 10

• 15

Find the greatest common factor of 24 and 48

• 4

• 12

• 24

• 48