Lesson 8

Workshop: Subtraction Practice

Est. Class Sessions: 2

Before the Lesson

The activities for the Workshop can be found in the Student Activity Book. You may choose to set the games for Part 3 of the Workshop in learning centers.

Review student work and progress from previous lessons to guide instructional decisions about the following Expectations:

E1.
Use and apply place value concepts to make connections among representations of numbers to the thousands using base-ten pieces, number lines, expanded form, and standard form.
E2.
Represent subtraction problems using base-ten pieces and number lines.

E3.
Subtract multidigit numbers using mental math strategies (e.g., composing and decomposing numbers, counting up) with number lines, a
200 Chart, and base-ten pieces.

E4.
Subtract multidigit numbers using paper-and-pencil methods (e.g., expanded form, compact).

In this Workshop, students will solve multidigit subtraction problems using a variety of strategies. Some students may be more proficient with some strategies and not as confident with others. Students may continually use a strategy that they are comfortable with but that may not be efficient. This Workshop provides problems that require students to use many different strategies. This gives them an opportunity to solve problems in ways that are natural to them and to consider the pros and cons of various methods. Students should have a collection of methods that they find useful for solving problems and they should understand the methods described by others. Students who are confident in using a variety of strategies will be able to begin to choose the strategy most efficient for any given problem. Knowing which strategies students are choosing or having trouble with will be helpful in guiding them. Students will also use estimation strategies to check the reasonableness of their solutions.

In Part 1 of the Workshop, all students will consider a variety of solution strategies and determine which leads to the correct answer. In Part 2, the Subtraction Practice Workshop Menu will guide students to appropriate subtraction practice. Students who are struggling can choose mostly 2-digit subtraction problems with 0–1 trades. Students who are more confident can challenge themselves with two- and three-digit subtraction with up to two trades. In Part 3, students need to be organized into groups of two players. Each group needs a deck of 0–9 digit cards (4 or 6 sets of 0–9 digit cards depending on which game they choose). Students will choose between two versions of the Difference War game based on their understanding of place value concepts and their abilities to subtract multidigit numbers.