1. Greatest
Common
Factor

2. 12 8 1 × 12 1 × 8 2 × 6 2 × 4 3 × 4 Greatest Common Factor
Step 1: Make a “T-Chart” for both numbers.
Step 2: Look for common factors between both numbers.
Step 3: Circle the greatest factor that both numbers have in common.
Step 4: This is the GCF.
Greatest Common Factor
Find the Greatest Common Factor (GCF) of 12 and 8. 12 8 1 × 12 1 × 8 2 × 6 2 × 4 3 × 4
The GCF of 12 and 8 is 4

3. Step 1: Make a “T-Chart” for both numbers.
Step 2: Look for common factors between both numbers.
Step 3: Circle the greatest factor that both numbers have in common.
Step 4: This is the GCF.
Greatest Common Factor
Find the Greatest Common Factor (GCF) of 16 and 24. 16 24 1 × 16 1 × 24 2 × 8 2 × 12 4 × 4 3 × 8 4 × 6
The GCF of 16 and 24 is 8

4. Step 1: Make a “T-Chart” for both numbers.
Step 2: Look for common factors between both numbers.
Step 3: Circle the greatest factor that both numbers have in common.
Step 4: This is the GCF.
Greatest Common Factor
Find the Greatest Common Factor (GCF) of 30 and 48. 30 48 1 × 30 1 × 48 2 × 15 2 × 24 3 × 10 3 × 16 5 × 6 4 × 12 6 × 8
The GCF of 30 and 48 is 6

5. Step 1: Make a “T-Chart” for both numbers.
Step 2: Look for common factors between both numbers.
Step 3: Circle the greatest factor that both numbers have in common.
Step 4: This is the GCF.
Greatest Common Factor
Find the Greatest Common Factor (GCF) of 32 and 40. 32 40 1 × 32 1 × 40 2 × 16 2 × 20 4 × 8 4 × 10 5 × 8
The GCF of 32 and 40 is 8

6. Greatest Common Factor
Step 1: Make a “T-Chart” for all 3 numbers.
Step 2: Look for common factors between all 3 numbers.
Step 3: Circle the greatest factor that all 3 numbers have in common.
Step 4: This is the GCF.
Greatest Common Factor
Find the Greatest Common Factor (GCF) of 18, 36, and 45. 18 36 45 1 × 18 1 × 36 1 × 45 2 × 9 2 × 18 3 × 15 3 × 6 3 × 12 5 × 9 4 × 9 6 × 6
The GCF of 18, 36, and 45 is 9

7. Greatest Common Factor and Fractions
Step 1: Make a “T-Chart” for numerator and the denominator.
Step 2: Look for common factors between both numbers.
Step 3: Circle the greatest factor that both numbers have in common.
Step 4: This is the GCF.
Greatest Common Factor and Fractions
You can find the Greatest Common Factor of a fraction’s numerator and denominator ,too.
What is the GCF of ? 9 12 9 12 1 × 9 1 × 12 3 × 3 2 × 6 3 × 4
The GCF of is 3. 9 12

8. Greatest Common Factor and Fractions
Step 1: Make a “T-Chart” for numerator and the denominator.
Step 2: Look for common factors between both numbers.
Step 3: Circle the greatest factor that both numbers have in common.
Step 4: This is the GCF.
Greatest Common Factor and Fractions
You can find the Greatest Common Factor of a fraction’s numerator and denominator ,too.
What is the GCF of ? 25 30 25 30 1 × 25 1 × 30 5 × 5 2 × 15 3 × 10 5 × 6
The GCF of is 5. 25 30

9. Greatest Common Factor and Fractions
Step 1: Make a “T-Chart” for numerator and the denominator.
Step 2: Look for common factors between both numbers.
Step 3: Circle the greatest factor that both numbers have in common.
Step 4: This is the GCF.
Greatest Common Factor and Fractions
You can find the Greatest Common Factor of a fraction’s numerator and denominator ,too.
What is the GCF of ? 24 32 24 36 1 × 24 1 × 32 2 × 12 2 × 16 3 × 8 4 × 8 4 × 6
The GCF of is 8. 24 32

10. Use “T-Charts” to find the GCF.
Your Turn!
Use “T-Charts” to find the GCF.
and 30
and 45 12 30 15 45 1 × 12 1 × 30 1 × 15 1 × 45 2 × 6 2 × 15 3 × 5 3 × 15 3 × 4 3 × 10 5 × 9 5 × 6
GCF: 6
GCF: 15

11. Use “T-Charts” to find the GCF.
Your Turn!
Use “T-Charts” to find the GCF. 18 36 21 35 3. 4. 18 36 21 35 1 × 18 1 × 36 1 × 21 1 × 35 2 × 9 2 × 18 3 × 7 5 × 7 3 × 6 3 × 12 4 × 9 6 × 6
GCF: 18
GCF: 7

12. Use “T-Charts” to find the GCF.
Your Turn!
Use “T-Charts” to find the GCF.
and 30
and 36 27 30 24 36 1 × 27 1 × 30 1 × 24 1 × 36 3 × 9 2 × 15 2 × 12 2 × 18 3 × 10 3 × 8 3 × 12 4 × 6 4 × 9 6 × 6
GCF: 3
GCF: 6

13. Use “T-Charts” to find the GCF.
Your Turn!
Use “T-Charts” to find the GCF.
, 15, and 21 12 15 21 1 × 12 1 × 15 1 × 21 2 × 6 3 × 5 3 × 7 3 × 4
GCF: 3