
Adjust the Niess Dynamic Function Machine initial and increment values so the "Carnival Bracelet #1" solution does not show.

Introduce Niess Dynamic Function Machine spreadsheet with the "Carnival Bracelet" problem:
To go on rides at the fair you must first pay the $7.50 entrance fee and then pay $1.50 for each ride. Some students choose to buy the $25 carnival bracelet which is good for one day’s entrance fee plus unlimited rides. Use the Dynamic Function Machine to determine for which numbers of rides is the $7.50 entrance fee plus $1.50 per ride less expensive than the carnival bracelet? For which numbers of rides is the $25 carnival bracelet less expensive than the $7.50 entrance fee plus $1.50 per ride? Is there a number of rides where the cost would be the same either way?

Adjust the Niess Dynamic Function Machine initial and increment values to show the intersection

Niess "Cell Phone #2" problem:
Juan and Sylvia each have a cell phone. They were comparing their costs to see who has the better deal. Juan’s company charges 20 cents for making a call and then charges 60 cents for each minute of the call. Sylvia’s company charges 30 cents per minute but charges 80 cents for making the call. All call charges are for 1minute minimum. How many minutes can they talk on the phone such that their charges are equal?

Demonstrate how to translate the cell phone problem into two algebraic equations, how to enter the equations into the function machine, how to adjust the initial and increment values to show a solution and finally how to rename the graph title and axis labels to match the cell phone variables.

Niess "Satellite/DVD #3" problem:
The Smith family is trying to decide between installing a satellite dish and receiving and movies through the satellite or purchasing a DVD and signing up for DVD rentals per month. The Smiths need to compare the cost of each option over several months in order to make an appropriate decision.
Satellite: One time installation of $29 and $49 per month for the service that allows them to unlimited access to their choice of movies with the stipulation that they must maintain this system for at least one year.
DVD: Purchase a DVD player for $250 and unlimited rental of DVDs for $30 per month.
Help the Smith family make a decision. For how months is the Satellite less expensive? For how many months is the DVD player with rentals less expensive? Is there a number of months when the cost is the same?

Demonstrate how to translate the "Satellite/DVD"problem into two algebraic equations, how to enter the equations into the function machine, how to adjust the initial and increment values to show a solution and finally how to rename the graph title and axis labels to match the cell phone variables.

"Airplanes" #4:
A plane initially at 28,000 feet is descending at a rate of 1800 feet per minute, and a second plane initially at 1500 feet is climbing at a rate of 2300 feet per minute. Determine how many minutes it will take for the planes to be at the same altitude. Create a chart that tracks their progression per minute until they pass each other.

Students work on their own to solve by translating the airplane problem into two algebraic equations, entering the equations into the function machine, adjusting the initial and incremental values to show a solution and finally renaming the graph title and axis labels. Students rename their spreadsheet with their <own name>airplanes and submit Niess Dynamic Function Machine to the teacher.

Students create their own Niess Dynamic Function Machine problem scenario to share with a partner. They also submit the new problem to the teacher saved as <own name>new problem.

After students share with a partner and edit their problem scenarios and function machines, they then are ready to share with the class.

References: Maggie Niess, Professor Emeritus Mathematics Education Science and Mathematics Education, Oregon State University, Corvallis, OR 97331,SED 522 online course
I love this lesson! I just spent time telling my kids how they use algebra when they are working with spreadsheets on Excel. My friend, who owns a local business, is always asking me to help to set up spreadsheets for his company. Such a valuable tool. I haven't looked through your lesson completely  but definitely plan on using parts of it. Thanks for the idea. It can be adapted to Geometry very well when working with surface area and volume.
This is a great lesson on systems of equations! I would like to know the process in creating a template for any type of problem like this; ie, is this a specific program that needs to be purchased? I like the visual of it. Can you email me with info on this?
Thank you for sharing and especially for the spreadsheet visual!
This is a great idea!!! Where do you get the machine that is needed for this lesson? I can definitely use this in my classroom. What a great way for kids to use the technology available to them to also check their work to see if they understand the concepts. It will also bring real life application of the software programs being used in the work place.