Transcript 4.3 Greatest Common Factors (GCF)

4.3 Greatest Common Factors
(GCF)
I can find the greatest common
factor of a set of numbers
Review
A factor is number that is multiplied by
another number to get a product
The greatest common factor is the
largest factor that two or more numbers
share.
Factors of 24:
Factors of 36:
1, 2, 3, 4, 6, 8, 12, 24
1, 2, 3, 4, 6, 9, 12, 18, 36
Common factors: 1, 2, 3, 4, 6, 12
The greatest common factor (GCF) of 24 and 36
is 12.
Example 1 shows three different methods for
finding the GCF.
Additional Example 1A: Finding the GCF
Find the GCF of the set of numbers.
28 and 42
Method 1: List the factors.
factors of 28: 1, 2, 4, 7, 14, 28
List all the factors.
factors of 42: 1, 2, 3, 6, 7, 14, 21, 42
Circle the GCF.
The GCF of 28 and 42 is 14.
Check It Out: Example 1A
Find the GCF of the set of numbers.
18 and 36
Method 1: List the factors.
factors of 18: 1, 2, 3, 6, 9, 18
List all the factors.
factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36 Circle the GCF.
The GCF of 18 and 36 is 18.
Try on your Own


16 & 28
24 & 56
Guided: using Distributive Property

15 + 25

36 + 72
Try on your own


10 + 90=
45 + 72=
LCM

LCM: Least Common Multiple:
The smallest number, other than
zero, that is a multiple of two or
more given numbers
Guided Practice

5&6

9 & 11
Try on Your own

3&7

4&6