1. Finding Greatest Common Factor

2. 8, 24 2 Use the prime numbers 2,3,5, and 7
Which can divide into 8 and 24 evenly?
8, 24 2

3. How many times does 2 divide into 8 and 24?
8, 24 2
4, 12

4. 2,3,5,7--Which prime number can divide into 4 and 12 evenly?
8, 24 2 2
4, 12

5. How many times does 2 divide into 4 and 12?
8, 24 2 2
4, 12
2, 6

6. 2,3,5,7—Which prime number can divide into 2 and 6 evenly?
8, 24 2 2
4, 12 2
2, 6

7. How many times does 2 divide into 2 and 6?
8, 24 2 2
4, 12 2
2, 6
1, 3

8. 2,3,5,7—Which prime number can divide into 1 and 3 evenly?
8, 24 2
4, 12 2
2, 6 2
1, 3
None of them can.

9. Last step- multiply all of the numbers going vertically on the left side of the problem.
8, 24 2 X X
4, 12 2 X
2, 6 2
1, 3
= 8
The GCF of 8 and 24 is 8.