GCF – Greatest Common Factor4-3

6.NS.4 I can find the greatest common factors of two whole numbers less than or equal to

100

LCM – Least Common Multiple

6.NS.4I can fin the least common multiple of two numbers less than or equal to 12

Greatest Common Factor

• What are we trying to find?• What are factors?• Can you write your own defintion?

Least Common Multiple

• What are we trying to find?• What are multiples?• Can you write your own defintion?

The Greatest Common Factor (GCF) of 2 numbers is the largest factor the 2 numbers have in common.

Factors of 24:

Factors of 36:

Common factors:

1, 2, 3, 4, 6, 8,

1, 2, 3, 4, 6,

The greatest common factor (GCF) of 24 and 36 is 12.

1, 2, 3, 4, 6, 9,

12,

12, 18,

24

36

12

• The Least Common Multiple (LCM) is the smallest number that is a multiple of two numbers.

• List the multiples and circle the smallest on they have in common

4: 4, 8, 12 , 16, 20, 24, 28, 32, 36, 40, 44, …

5: 5, 10, 15, 20, 25, 30, 35, 40, 45, . . .

Find the GCF and LCM

• 9 , 12• GCF:

• LCM:

Keep them Straight……

• Focus on the key words: Multiple and Factors.– Least Common Multiple– Greatest Common Factor

• Multiple:

• Factors:

Find the Greatest Common Factor

• 3, 4

• 12, 18

• 9, 21

Find the Least Common Multiple

• 2, 10

• 5, 6

• 3, 12

.

How well can you find the LCM and GCF of two numbers?

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Watch and Learn…..

• LCM Video • GCF Video