T3
Use the Distributive Property to generate equivalent expressions * NS.4
Lesson 1
The secret I use to multiply large numbers mentally is called the Distributive Property.
First, I decompose one of the factors in the expression.
For example, in the expression 7 ⋅ 12, I decompose the 12 into 10 + 2. Then, I multiply the 7 by 10 and the 7 by 2 and add up the products.
7 ⋅ 12 = 7 (10 ⋅ 2)
I want you to think of the next 10 problems like puzzles.
When you figure it out, be sure to share the secret with each of your group members.
#1 notice that the number outside of the parentheses is a common factor of the numbers on the other sides of the equals sign
You are all going to do some of these. But, there are three things for you to keep in mind. First, do your own. Second, you choose where to start. Third, check your work with the students around you, and if you need help, get help. And if someone needs help, give help.
3. Stuck? Choose to persevere: review your thinking, try different approaches, ask for help, search