Problem Solving with Area

Ask several students to share their solution strategies for Questions 14–15. In Question 14, students may use different strategies to divide the shape into smaller rectangles. See Figure 1 for one possible solution.

Students are asked to evaluate Levi's solution strategy in Question 15. Students should recognize that Levi counted the middle square twice as he was finding the area, once for the horizontal rectangle and once for the vertical rectangle. Since this is a flat shape, this section is only counted once in the area. This means that Levi's solution strategy is not correct.

After discussing these two problems, assign Check-In: Questions 16–17 for students to complete independently or with a partner. Before students begin their work, refer them to the Math Practices page in the Student Guide Reference or to the display of the Math Practices page. Have students read Math Practices 1, 2, 5, and 6. Ask students to think about the strategies they have used in this lesson and to use these strategies as they are completing these probems. Remind students that they need to clearly communicate their strategies in their explanations and that they need to use labels in their solutions.