1. Warm - Up Review Notes… What is a Factor?
Describe how you would list the factors of a number?

2. Greatest Common Factor
Topic
Greatest Common Factor
GCF

3. Tonight’s Homework (8/29)
Find the greatest common factor of the numbers. Using PRIME FACTORIZATION or THE FIGURE FOUR.
99 and and 198
88 and and 450

4. Essential Question
How would you explain the process of finding the greatest common factor (GCF) of two or more numbers?

5. Key Terms Common Factor Greatest Common Factor (GCF) Factor Tree
Factor Rainbow
Figure Four

6. Common Factor
A whole number that is a factor of two or more numbers

7. Greatest Common Factor (GCF)
The Greatest of the Common Factors
Another name for Greatest Common Factor is…
Greatest Common Divisor (GCD)
- This is used when working with fractions

8. Factor Tree
A diagram that can be used to write the prime factorization of a number.

9. Factor Rainbow
A visual used to list the factors of a number in numerical order.

10. Figure Four
A method, using division, used to help find the Greatest common factor between two numbers

11. Example 1
Write the Factors of 28, 42, and 70
28:
70:

12. Example 1 Write the Factors of 28, 42, and 70 28: 1, 2, 4, 7, 14, 28
42: 1, 2, 3, 6, 7, 14, 21, 42
70: 1, 2, 5, 7, 10, 14, 35, 70

13. Example 1 Write the Factors of 28, 42, and 70 28: 1, 2, 4, 7, 14, 28
42: 1, 2, 3, 6, 7, 14, 21, 42
70: 1, 2, 5, 7, 10, 14, 35, 70

14. Guided Practice
Find the GCF…
16, , 91

15. Using the GCF to Solve Problems
(see pg. 10)
(pg. 13 – number 44)

16. Using Prime Factorization to Find the GCF
Find the Prime Factors of 90 & 150
Use a factor tree to solve