Tuesday, October 8, 2013

Buttons and Applications of Linear Equations #MTBoS

I've decided to respond to the following prompt for MTBoS:

What is one of your favorite open-ended/rich problems?  How do you use it in your classroom? (If you have a problem you have been wanting to try, but haven’t had the courage or opportunity to try it out yet, write about how you would or will use the problem in your classroom.)

My Algebra 1 classes have been working on simplifying algebraic expressions and solving equations.  Not too long ago we complete this activity with simplifying expressions, and now I'm building on that by solving equations.

Before class started I put the same amount of buttons in a sealed envelope (paper that was staples together) and labeled it "X Buttons"

I started class by showing the students the poster I made below, and that each envelope has the same amount of buttons.  I put students into groups and asked them to discuss how they were going to figure out how many buttons were in each envelope and to finally write their work along with their answer.

Below are three of the responses that I received.  We discussed each one and how they compare to each other.  

Tomorrow, the students will be creating their own posters with snowflakes instead of buttons, and solving each others problems.  I will keep you posted.  


  1. Nice! I wonder if it would work to make this self-checking by using flaps instead of envelopes. Or maybe replace one of the envelopes with a flap? Next step: linking two posters with two unknowns....

  2. Awesome! This will be a great problem for after Fall Break!

  3. I love the tangible/puzzle aspect of this problem. I love the three very different samples of student work and that you used them in your class discussion. They really show the validity of multiple approaches.