Function Machine

Download The Assignment:
You may download the assignment by clicking on the following link: Function Machine Overhead
You may download the assignment by clicking on the following link: Function Machine Assignment


Objectives:
-Students will define what a function is.
-Students will solve for y given x in simple functions.
-Students will solve for x given y in simple functions.
-Students will infer what a function is by looking at its data. |
-Students will define what an order pair is.

Introduction:
Have you ever read Dr. Suess's book the Star Bellied Sneetches? Well if you haven't you need to go read it now and come back afterwards, if you have; however, you know that functions work very similar to the machine found in this book. You put an x in, and you get a y out. You put a y in and you get an x out. You put in a Sneetche and you get a Star Bellied Sneetche out.

This lesson lets you show your students what a function works like, by using a machine as an example.

Setup:
First you must teach the class what a function is, namely, a function is a set of rules that operate upon an input (Domain) and an output(Range). Or in simple terms, a function is an equation with an input and an output, or two variables.

Take the sheet titled Function Machine Overhead and make... and overhead of it. Write a few equations in the box and have students give you inputs and you can give them outputs.

Explain to the class that there are many different ways to write the results. x = 5, y = 12 for example or a table, but the preferred way to write the data is as an ordered pair. Explain and define what an order pair is to your students.

After working through several examples as a class give the students the assignment Function Machine Assignment. The first page has four function machines and it is the students responsibility to to make a table and write 4 ordered pair for each function. If you want to have the students pick any number they want you may, or you may supply the numbers for the xs or if you want the ys yourself.

Also explain that functions are useful in the fact that the input and output can represent real world situations, such as a percentage on a test, the temperature in Farienhiet instead of Celsius, or the number of pizzas required at a part depending on the number of guests.

When the students finish the first side of the assignment, have them work in groups to try and guess the functions that belong in the machines on the other page.

Expected Student Behavior:
Students generally are receptive to this visual explanation of math, and want to listen. The definition for function and ordered pair; however, must be practiced and repeated in order for the students to know and learn it.

Possible Class Discussion:
After the students are done with the assignment some possible ideas for class discussion are:
1) What other types of situations might use an input and an output?
2)What strategies did you use to find the missing function?

Accommodations:
The assignment is quite straight forward, but if it is too easy for your students give them the y values and have them find you the x values instead of the other way around.

Feedback:
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If you have a minute or two to spare and would like to share how this lesson went in your classroom or if you have any questions, think that the lesson plan could be clearer, find a typo or a mistake, or have any other great lesson plan ideas that you would like to share please e-mail us at: teacherresources@unpracticalmath.com