Education Technology

# Activities

• ##### Subject Area

• Math: Algebra I: Linear Functions
• Math: PreAlgebra: Linear Functions
• Math: PreAlgebra: Expressions
• Math: PreAlgebra: Number Sense and Operations
• Math: Middle Grades Math: Algebraic Thinking
• Math: Middle Grades Math: Problem Solving

6-8

60 Minutes

• ##### Device
• TI-30X IIB
• TI-30X IIS
• TI-34 II Explorer Plus™
• ##### Other Materials
This is Activity 5 from the EXPLORATIONS Book:
Math Investigations with the TI-30X IIS and TI-34 II: Activities for the Middle Grades

The following materials are required for this activity:
• Colored pencils, markers or crayons
• Straight edge

## CDs Anyone?

#### Activity Overview

Students write rules for real world functions. They make a table to compare function values and graph linear functions on the coordinate plane.

#### Before the Activity

• See the attached PDF file for detailed instructions for this activity
• Print pages 40 - 45 from the attached PDF file for your class
• Study the calculator keystrokes
• #### During the Activity

Distribute the pages to the class.

• Write function rules for each company's discount plan
• Calculate the cost of buying 1 through 15 of CDs from each company
• Tabulate the results
• Plot a graph of Cost of CDs versus Number of CDs
• Analyze the graph and determine which company has the best plan and under which condition
• #### After the Activity

Students complete the Student Activity pages and answer questions.

• Review student results
• As a class, discuss questions that appeared to be more challenging
• Re-teach concepts as necessary