1. Let’s Talk Multiplication

2. How would you solve the following?
36 x x 8 64 x 6

3. What can you do to the 4 to simplify the problem?
Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
36 x 4
What can you do to the 4 to simplify the problem?

4. 36 x 4 36 x (2 + 2) (36 x 2) + (36 x 2) 72 + 72 = 144 Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
36 x 4
36 x ( )
(36 x 2) + (36 x 2)
= 144

5. What can you do to the 36 to simplify the problem?
Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
36 x 4
What can you do to the 36 to simplify the problem?

6. 36 x 4 (30 + 6) x 4 (30 x 4) + (6 x 4) 120 + 24 = 144 Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
36 x 4
(30 + 6) x 4
(30 x 4) + (6 x 4)
= 144

7. What can you do to the 8 to simplify the problem?
Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
203 x 8
What can you do to the 8 to simplify the problem?

8. Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
203 x 8
203 x (4 + 4)
(203 x 4) + (203 x 4)
=1624

9. What can you do to the 203 to simplify the problem?
Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
203 x 8
What can you do to the 203 to simplify the problem?

10. Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
203 x 8
( ) x 8
(200 x 8) + (3 x 8)
1624

11. What can you do to the 6 to simplify the problem?
Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
64 x 6
What can you do to the 6 to simplify the problem?

12. 64 x 6 64 x ( 3 + 3) (64 x 3) + (63 x 3) 192 + 192 384 Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
64 x 6
64 x ( 3 + 3)
(64 x 3) + (63 x 3)
384

13. What can you do to the 64 to simplify the problem?
Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
64 x 6
What can you do to the 64 to simplify the problem?

14. 64 x 6 (60 + 4) x 6 (60 x 6) + (4 x 6) 360 + 24 384 Let’s simplify
Can you decompose one of the factors to make the problem easier to solve mentally?
64 x 6
(60 + 4) x 6
(60 x 6) + (4 x 6)
384

15. Let’s Partner Practice
Each partner will choose a different factor to decompose to simplify the problem.
Compare answers.
Explain your process to your partner.
89 x 7

16. Let’s Partner Practice
Each partner will choose a different factor to decompose to simplify the problem.
Compare answers.
Explain your process to your partner.
112 x 8

17. Let’s Partner Practice
Each partner will choose a different factor to decompose to simplify the problem.
Compare answers.
Explain your process to your partner.
43 x 9

18. Let’s Partner Practice
Each partner will choose a different factor to decompose to simplify the problem.
Compare answers.
Explain your process to your partner.
602 x 12

19. Let’s Partner Practice
Each partner will choose a different factor to decompose to simplify the problem.
Compare answers.
Explain your process to your partner.
43 x 13

20. On Your own
Solve the following problems using the strategy we learned today.
You choose which number to decompose.
432 x x x x 82
34 x x x x 19
16 x x x x 17

21. So, what do you think? Was the strategy easy to learn?
What kind of factor (larger or smaller) did you prefer to decompose? Why?
Had you used this strategy to multiply before?
Does this strategy make mental math simpler?
Do you think you would be more accurate with this method or the traditional method? Why?