1. Finding all the Factors
*Divisibility Tricks*

2. Problem of the Day
Mentally Solve: 28+42

3. factor x factor = product
Let’s Review
Find one factor pair of 14.
2 x 7 = 14
factor x factor = product

4. Find all the factor pairs
Find all factor pairs of 12.
1 x 12 = 12

5. Find all the factor pairs
1 x 12 = 12
Find all the factor pairs
2 x 6 = 12
Find all factor pairs of 12.

6. Find all the factor pairs
1 x 12 = 12
Find all the factor pairs
2 x 6 = 12
Find all factor pairs of 12.
3 x 4 = 12

7. Find all the factor pairs
1 x 12 = 12
Find all the factor pairs
2 x 6 = 12
Find all factor pairs of 12.
3 x 4 = 12
Write the factors in order from least to greatest.
Factors of 12: 1,2,3,4,6,12

8. Find all the factor pairs
Find all factor pairs of 12.
Factors of 12:
When you reach the other side of the rainbow you have found all of the factors!
Check every number under the rainbow to see if it a factor.
After 1 comes 2!
Did you find all the factor pairs?
Check with the Factor RAINBOW.
Always start with 1 and the number.
3 4
This slide is optional… delete if you do not want your students to use this strategy.

9. I know 2 is a factor of 12, because 12 is divisible by 2.
How do I know if a number is a factor?
I check to see if it is divisible.
Divisible means that you can divide a number by another number and the remainder is 0.
I know 2 is a factor of 12, because 12 is divisible by 2.
What does divisible mean?

10. 13 62 20 31 88 Is the number divisible by 2? Do you see any patterns?
YES NO
Have students check other common numbers (3,5,6,9,10) for patterns to develop the divisibility rules.
Do you see any patterns?

11. Which numbers are a factor of 45.
Ⓐ 1 Ⓑ 2 Ⓒ 3 Ⓓ 5 Ⓔ 10 Ⓕ 15
A,C,D,F

12. Let’s find all of the factors of 72…
1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72

13. On Your Own
1) Page #3, 5, 10, 13, 17
2) Math Choice Board