# Comparing Value for Money: Baseball Jerseys

## Mathematical goals

This lesson unit is intended to help you assess how well students are able to:

- Interpret a situation and represent the variables mathematically. Select appropriate mathematical methods to use. Explore the effects of systematically varying the constraints.
- Interpret and evaluate the data generated and identify the break-even point, checking it for confirmation. Communicate their reasoning clearly.

## Introduction

- Before the lesson students attempt the task individually. After reviewing responses, you formulate questions for students to consider when planning improvements to their work.
- At the start of the lesson, students think individually about the questions posed.
- Next, students work in small groups to combine their thinking and work together to produce a collaborative solution to the
*Baseball Jerseys*task, in the form of a poster. - In the same small groups, students evaluate and comment on sample responses, identifying the strengths and weaknesses in these responses and comparing them with their own work.
- In a whole-class discussion students compare and evaluate the strategies they have seen and used.
- In a follow-up lesson, students reflect for 10 minutes on their work and what they have learned.

## Materials required

- Each individual student will need a copy of the assessment task:
*Baseball Jerseys,*some plain paper, a mini-whiteboard, pen, and eraser, and a copy of the*How Did You Work?*questionnaire.

- Each small group of students will need a large sheet of paper, some felt tipped pens, and copies of
*Sample Responses to Discuss*. - Provide calculators and graph paper only when requested.
- There is a projector resource to support whole-class discussions.

## Time needed

15 minutes before the lesson, a 70-minute lesson (or split into two shorter ones), and 10 minutes in a follow-up lesson. Timings given are only approximate.

## Lesson Type

## Mathematical Practices

This lesson involves a range of *mathematical practices* from the standards, with emphasis on:

- MP1: Make sense of problems and persevere in solving them
- MP2: Reason abstractly and quantitatively
- MP3: Construct viable arguments and critique the reasoning of others
- MP4: Model with mathematics
- MP5: Use appropriate tools strategically
- MP6: Attend to precision
- MP8: Look for and express regularity in repeated reasoning

## Mathematical Content Standards

This lesson asks students to select and apply mathematical content from across the grades, including the *content standards:*

- 8.EE: Understand the connections between proportional relationships, lines, and linear equations.
- 8.EE: Analyze and solve linear equations and pairs of simultaneous linear equations.
- 8.F: Use functions to model relationships between quantities.