G8

Copyright © Copyright © Swun MathSwun Math (^) Grade 8 Unit 4 Lesson 2 P TE

Challenge Problems

Directions: Identify the error, make the correction, and explain your thinking.

1. Bobby’s work:
   3 푥푥= 12

푥푥= 36

Solution:

Bobby multiplied the 3 and 12, but he should have

divided. The original equation had multiplication and

the inverse operation of multiplication is division.

3 푥푥

3 =

12

3

푥푥= 4

2. Cindy’s work:
   푚푚
   5

= 15

푚푚= 3

Solution:

Cindy divided 15 by 5, but she should have multiplied.

The original equation had division and the inverse

operation of division is multiplication.

5 ∙

푚푚

5 =^15 ∙^5

푚푚= 75

Extension Activity

* MP1: Make sense of the problem and persevere in solving it.

* MP4: Apply mathematics in everyday life.

Write four equations, one with each operation, so that each has a solution of ─4.