Lesson objective: Apply understanding of the relationship between multiplication and division.

This lesson provides an opportunity for students to apply their knowledge and understanding of division to a real-life situation. Students are asked to find the best deals from the prices given at two different stores. They will need to first calculate the cost of one item from a known cost of a group of items. The cost of a single item will help to find the cost of uniforms, socks and caps for a team of nine.

Key Concept students will use:

Skills students will use:

- Using drawings and equations to represent and solve multiplication and division situational problems involving equal groups, arrays, and measurement quantities (Grade 3, Unit 1 & 7)
- Interpreting quotients of whole numbers as a number of shares (partitive or distribution division) and a number of groups (quotative or measurement division) (Grade 3, Unit 1 & 7)
- Interpreting products of whole numbers as a number of groups or a number of objects (Grade 3, Unit 1)
- Organizing groups of objects in an array as a number of equal groups (Grade 2, Unit 13)

Students engage in Mathematical Practice 1 (Make sense of problems and persevere in solving them) as they understand that they are making equal groups or parts and using division. They will persevere to find related facts or equations to represent an array or model.

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they form distinguishable groups, rows or jumps in a drawing or representation. These can also help them make sense of how a multiplication and division equation can be used to represent the drawing or group of tiles or counters.

**Key vocabulary:**

- array
- divide
- equal groups
- equation
- quotient
- related facts
- repeated subtraction
- representation

**Special materials needed:**

- base ten blocks to reason with, such as breaking apart numbers
- manipulatives such as square tiles, counters or cubes