1. Greatest Common Factors a.k.a. GCF

2. Greatest Common Factors
When two numbers share a factor, that factor is called a common factor.
Factors of 8: 1, 2, 4, 8
Factors of 12: 1, 2, 3, 4, 6, 12
The common factors of 8 and 12 are 1, 2, and 4.
The greatest common factor is the largest factor shared by two or more numbers.
The greatest common factor of 8 and 12 is 4.

3. Examples
Find the common factors and greatest common factor of 10, 20, and 30.
First list the factors of each number.
factors of 10: ________________________
factors of 20: ________________________
factors of 30: ________________________
Then list all of the common factors: ___________
Finally, compare these factors to find the greatest common factor: __________

4. TOTD 1/8/15
List all the factors of each number and then identify the number as prime or composite.
35:_______________ P or C
51: _______________ P or C
List the factors of each number. Then find the greatest common factor of the numbers.
3) 12, 14: ___________________GCF ____________
4) 6, 21: ____________________GCF ____________
Multiply. 5) 8.91 x 3.2
Divide. 6) ÷ .9