Z. Check Subtraction with Addition
Solve the problem. Then show how to check your answer with addition.
- 215
− 72 - 99
− 75 - Show how to use a mental math strategy to solve Question B.
Lesson 7
Make Connections with Subtraction
Est. Class Sessions: 2Daily Practice and Problems
Teacher Notes
X
Have base-ten pieces, 200 Charts, number lines, and Subtraction Strategies Menus readily available.
- Possible response: I thought of money. 99 is close to $1.00 and I subtracted 3 quarters for the 75, which leaves one quarter or 25. Then I took away the extra one from the 25 to get 24.