GCF and LCM and Some Other Fun

What does GCF stand for?

• Greatest Common Factor

• Go Catch Fish

• Least Common Multiple

• Laugh Out Loud

What does LCM stand for?

• Least Common Multiple

• Let's Count Mice

• Greatest Common Factor

• By the way...

Factors of 12: 1, 2, 3, 4, 6, 12

Factors of 15: 1, 3, 5, 15

What is the GCF of 12 and 15?

• 3

• 1

• 5

• 6

Factors of 20: 1, 2, 4, 5, 10, 20

Factors of 40, 1, 2, 4, 5, 8, 10, 20, 40

What is the GCF of 20 and 40?

• 20

• 5

• 2

• 4

Multiples of 4: 4, 8, 12, 16, 20, 24, 28, 32, 36,...

Multiples of 6: 6, 12, 18, 24, 30, 36, 42,...

What is the LCM of 4 and 6?

• 12

• 24

• 36

• 2

Which number is NOT prime?

• 9

• 11

• 13

• 5

Which number is prime?

• 13

• 8

• 12

• 21

The prime factorization of a number is:

 $2\times3\times3$  
What is the number?

• 18

• 8

• 12

• 9

What is the GCF of 36 and 45?

• 9

• 100

• 52

• 180

What is the GCF of 4 and 6?