Refer students to the Subtraction Strategies Menu in the Student Activity Book. See Figure 17. Ask them to compare the strategies on the menu to the strategies the class collected in this lesson and to the strategies of Mrs. Dewey's students shown in the Student Guide.
- Are the strategies you used in Questions 11 and 12 similar to one of the strategies represented on this menu?
- Are there any other strategies that we used that are not shown on the Subtraction Strategies Menu?
- Do you think we should add a strategy to the menu?
The blank box on the Subtraction Strategies Menu is for students to add either their own invented strategy or reference another strategy.
- Is this new strategy a mental math strategy or a paper-and-pencil strategy?
Identify a mental math strategy with a cloud.
Assign Check-In: Questions 14–17 in the Subtraction pages in the Student Guide.
Use Check-in: Questions 14–17 and the corresponding Feedback Box in the Teacher Guide to assess students' abilities to represent and solve subtraction problems using base-ten pieces and number lines [E3], solve addition and subtraction problems using mental math strategies [E4], subtract multidigit numbers using paper-and-pencil methods [E7], and choose appropriately from among mental math, estimation, and paper-and-pencil methods to add and subtract whole numbers [E9].
The Lesson 7 Workshop provides targeted practice.
