Greatest Common Factors

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 greatest common factor of 4 and 8?

• 2
• 8
• 4
• 1

What are the factors of 16 and 24?

• 16-1, 3, 6, 12, 16
  24-1, 2, 4, 6, 24
• 16-1, 2, 4, 8, 16
  24-1, 2, 3, 4, 6, 8, 12, 24
• 16-16, 32, 48, 54
  24-24, 48, 72, 86
• 16- 1, 2, 16
  24-1, 2, 12, 24

Which is a factor of 15?

• 2
• 3
• 4
• 6

Which of the choices is a factor of 10?

• 2
• 4
• 6
• 8

What is the greatest common factor of 8 and 10?

• 1
• 3
• 4
• 2

What is the greatest common factor of 4 and 16?

• 4
• 2
• 1
• 16

What is the greatest common factor of 16 and 24? 

• 6
• 2
• 4
• 8

What is the greatest common factor of 8 and 10?

• 1
• 3
• 4
• 2