# The Guitar Class: MAPs Activity- Cutting out what you don’t need

Once again I am using the Shell Center resources for class, this time looking at Modeling Situations with Linear Equations.  Once again, I am looking at the student handout and although it is designed as a pre-assessment, I am wondering why they are supplying students with so much information- time to get the scissors out….

The Guitar Class:

To be totally honest here, I’m scrapping pretty much the whole handout and start from scratch, here is what I will show students.

Students should come up with ideas about rent, how many students are in the class, and how much each student should pay for the class.  They should also sketch a graph starting at a negative balance (showing the rent for the space) and increasing with each student enrolled.  I will then ask them to write down answers to the following questions on their paper:

Teacher Questions:

What values for each factor did you assign?

How did that determine where to start your graph?

How did that effect your Axes? How did it effect your scale?

What do you notice about your graph?  (hopefully they say 2 things, it’s increasing at a steady rate per student, and that is crosses the X axis)

Students will have a varied set of values for each factor, and that is OK, their graphs will all have the same general look, and they should recognize that where it crosses the X axis is where the music teacher breaks even for cost.  I don’t want to give away anything with this question, it provides a great platform for students to provide ideas and values, as well as creating their own ideas on how to graph the scenario.  Looking at each individual’s work will give me instant information on how much the student comprehends the material and what I need to address.

As students are done with their graphs and our group discussion is when I would put back in the original scenario from their handout:

I do not think I will ask students to write an equation right away, giving students the proposed values instead. I would then ask these questions for students to answer on their paper:

Teacher Questions:

What is the situation the music teacher faces? (using these values)

What is the teacher’s balance at the beginning of the class?

How does each student effects that balance?

Write an equation representing this situation.

I also would not show them questions 3 or 4, I would instead ask verbally these questions, have students record their thoughts and discuss each one as a whole class at the end of the hour:

Teacher Questions:

How can we determine the teacher’s total cost.  Write that as an equation.

How can we determine the teacher’s total profit?  Write that as an equation.

What factors do we need to consider to determine the cost for each student?  Write that as an equation.

Are there values that are unreasonable to charge students for taking his class?  Explain.

I will be trying this out with my groups tomorrow.  I plan on engaging their creativity and mind- which will produce great ideas to discuss.  I realize that this is a pre-assessment for their unit, but students will provide me with enough information on where their skills lie with my student handout and follow up questions.  I will write a follow-up to see if I “Cut too Much.”