# Choosing a Cell Phone Plan Using Linear Equations

By Susan LoFranco on Apr 24, 2017

• Solve simple algebraic equations with one variable using addition and subtraction

## Materials

• Four Quadrant Graph Paper - Bold lined or raised
• Markers, dots, tape to connect dots, straight edge
• Comparing Cell Phone Plans - Instruction sheet

If you would like the student to do independent research on the different types of cell phone plans following are websites for Verizon, ATT, Sprint and TMobile to begin research. ## Procedure

• Review Vocabulary: Linear equation, variable (some number)
• Review with student the question:  A cell phone plan costs \$45.00 per month with the cost for texting an added \$0.25 per text.
• Together write a linear equation, using the students media of choice,  which represents the monthly cost if the user sents t messages. (y=45+0.25t)
• When the student is confident in the ability to write the linear equation have the student calculate the monthly cost if 100, 200 and 300 text messages are sent.
• Graph the results of the monthly costs with the number of text messages on the x axis and monthly costs on the y axis.
• Using the Comparing Cell Phone Plans - Instruction Sheet - review the instructions with the student.
• Once the student is confident, have him/her complete the task using the students media of choice. ## Variations

• This is a lifetime skill for the student.  The same type of analysis can be done for cable services, bundled or unbundled, streaming services, group dinners or rental costs. comparing_cell_phone_plans.doc