Lesson objective: Solve word problems using the relationship between multiplication and division.

This lesson provides an opportunity for students to apply their knowledge and understanding of multiplication and division as inverse operations to a real-life situation. Students are asked to figure out the individual cost of t-shirts from different stores to see which store has the better deal. They also need to be ready to share why they think their strategy is the most efficient way to solve the problem.

Key Concept students will use:

- You can use the relationship between multiplication and division to multiply and divide within 100

Skills students will use:

- Their understanding of multiplication and division as inverse operations.
- Thier ability to write equations with an unknown quantity.
- The ability to choose which strategy would be most efficient in solving the problem.

Students engage in Mathematical Practice 8 (Look for and express regularity in repeated reasoning) as they notice repetitive actions in computation when solving problems. For example, students can use skip counting or repeated addition or subtraction to solve a multiplication or division problem.

**Key vocabulary: **

- division
- efficient strategy
- inverse operations
- multiplication
- relationship
- unknown quantity