Greatest Common Factor

Which number is not a factor of 24?

• 6
• 8
• 3
• 14

Which number is a factor of 6?

• 12
• 2
• 8
• 10

Which set of numbers show all the factors for 15?

• 7, 8
• 1, 15
• 1, 3, 5, 15
• 3, 5, 15

A prime number is...

• a number that has only one factor.
• a number that has at least two factors.
• a number that has more than two factors.
• a number that has only two factors.
  (1 and itself)

What is the greatest common factor of 6 and 21?

• 6
• 2
• 3
• 7

What is the GCF of 4 and 12?

• 3
• 1
• 6
• 4

What is the GCF of 20 and 30?

• 5
• 2
• 10
• 20

GCF of 15 and 35

• 15
• 3
• 7
• 5

GCF of 12 and 28

• 3
• 6
• 2
• 4

GCF of 28 and 40

• 2
• 4
• 7
• 8