My algebra students have been studying transformations of quadratic functions – most specifically, how does changing “a” and/or “c” in a quadratic function written in the form y = ax^2 + c impact the graph when compared to the graph of the parent function f(x) = x^2?
Students have had a lesson, homework, and a chance to examine graphs using graphing calculators and/or Desmos, but some students still weren’t “seeing it”.
Inspired by this blog post, I used Desmos to create a “Quadratic Chain” activity. Tonight is a “no-homework night” across our district, so I felt that devoting the last 20 minutes of class to this cooperative task would be a good wrap-up.
Boy was I wrong.
It was… an AMAZING wrap-up! Why?
THE CONVERSATIONS!
I was absolutely beaming as I walked around the room, watching students compare, discuss, disagree, and A-HA all over themselves! Boy did I underestimate this one. It was great, and I will do it again! We even created a “gallery” for our “chains” on the wall outside my classroom. Quite retro chic if you ask me. 😉
Here’s the file if you’d like to give it a try! My only wish is that the numbers on the axes were a little larger, but it didn’t seem to impact the activity today one bit.
Quadratics_Chain_Transformations_Practice
Here’s a thorough explanation about how this type of activity works.
Here is a video I took with my iPhone while walking around during student conversations. It doesn’t do justice to all the math talk that was happening, but it’s a little sample!

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Hi Cathy,
Thanks for sharing. As I am unfamiliar with Desmos, I will have a look into it.
If you like chaining excersices, you should also check Formulator Tarsia at http://www.mmlsoft.com/index.php/products/tarsia
Regards,
Jörgen (teacher math 12 – 17 yrs in The Netherland
Thanks so much for sharing – this looks like a great tool for chaining and puzzle exercises! Check out Desmos as well – it’s a free online graphing calculator, but its dynamic platform makes it so much more than a calculator: desmos.com