Strategies
How can we represent a multiplication problem? (Hint: 3 different ways)
Write an equation, draw an array, or draw equal groups
How can you decompose 3 to find the product of 3 x 9?
Decompose the 3 into 1 and 2.
3 x 4 = ?
Show your work.
3 x 4 = ?
1 x 4 + 2 x 4
4 + 8 = 12
3 x 4 = 12
Which equation represents how to find the product for the array?
X X X X X X X
X X X X X X X
X X X X X X X
X X X X X X X
A. 4 x 7 = 4 x 7 + 4 x 7
B. 4 x 7 = 4 x 4 + 4 x 2
C. 4 x 7 = 4 x 5 + 5 x 2
D. 4 x 7 = 4 x 5 + 4 x 2
D. 4 x 7 = 4 x 5 + 4 x 2
How do we find the product of factors that do not have a pattern? (ie. 4x7)
Decompose one of the factors, create two new equations. Find the products of both equations, and add them together.
How can you decompose 4 to find the product of 4 x 7?
Decompose the 4 into 2 and 2.
4 x 9 = ?
Show your work.
4 x 9 = ?
2 x 9 = 18
18 + 18 = 36
4 x 9 = 36
Which expression is equivalent to 3 x 5?
A. 1 x 2 + 2 x 3
B. 1 x 5 + 2 x 5
C. 3 x 5 + 3 x 5
D. 3 x 5 + 3 x 1
B. 1 x 5 + 2 x 5
What are two different ways to decompose 4 x 9
How can you decompose 6 to find the product of 6 x 8?
Decompose 6 into 3 and 3 or 4 and 2.
6 x 5 = ?
Use 1s facts and 5s facts.
Show your work.
6 x 5 = ?
1 x 5 + 5 x 5 =
5 + 25 = 30
6 x 5 = 30
The array below represents a multiplication problem.
X X X X X
X X X X X
X X X X X
X X X X X
1. Show how you can decompose the array to multiply 4 x 5.
2. Write an equation that represents the decomposed array.
3. What is the product?
1. Decompose 4 into 2 and 2
2. 2 x 5 + 2 x 5
3. 10 + 10 = 20
Decompose the 7 into 5 and 2. Multiply 5 x 8 = 40 and 2 x 8 = 16. Then add 40 + 16 = 56. 8 x 7 = 56
How can you decompose 8 to find the product of 8 x 3?
Decompose the 8 into 4 and 4 or 5 and 3.
3 x 8 = ?
Use 5s facts
Show your work.
3 x 8 = ?
3 x 3 + 3 x 5 =
9 + 15 = 24
3 x 8 = 24
John plants 8 tomato plants in 6 rows. How many tomato plants did John plant?
48 tomatoes
6 x 8 = ?
5 x 8 + 1 x 8 =
40 + 8 = 48
How can knowing the product of 4 x 6 = 24 help you find the product of 8 x 6?
8 can be decomposed into 4+4. We can double the product, 24 (24+24), to find the product, 8 x 6 = 48.
How can you decompose a factor to find the product of 7 x 9?
Decompose the 7 into 2 and 5 or decompose the 9 into 4 and 5.
7 x 3 = ?
Use 5s facts
Show your work
7 x 3 = ?
5 x 3 + 2 x 3 =
15 + 6 = 21
7 x 3 = 21
Rachel wants to decompose a factor to find the product of 4 x 7. Number the steps in the correct order to find the product.
__ Find the product of 4 x 7 = 28.
__ Find the product of 2 x 7.
__ Decompose the 4 into 2 and 2.
__ Add 14 + 14
4. Find the product of 4 x 7 = 28.
2. Find the product of 2 x 7.
1. Decompose the 4 into 2 and 2.
3. Add 14 + 14