My favorite tools for teaching transformations from parent functions are the Desmos Marbleslides. This is the first year that I have been able to use these activities to cement our learning across function families in our Algebra 2 classes. While these aren’t exactly skill and drill practice, they do seem to give students similar opportunities to do the repetitive work that is needed to build procedural fluency.

Just a few of the reasons I love these marbleslides…

- They are consistently motivating, fun, and engaging
- There are opportunities for creative solutions
- They present open problems with multiple solutions, battling the idea that all math problems have exactly one answer that is in the back of the textbook!
- As a teacher, I am always interested in and surprised by student solutions – very different from much of my grading
- Students demonstrate perseverance through these challenges – they really want to come to solutions, and will keep working until they succeed

I made my first custom Marbleslide for students to practice transforming absolute value functions. My activity is basically an exact copy of the Desmos team’s work, but with Absolute value equations. The custom activity was very easy to build, and I am turning over some more creative ideas to explore now that I have done this.

I am pretty sure that part of our success with our understanding of transformations has come from the course map this year. We are basing this year’s sequence of topics around families of functions. We began with an informal study, just looking at shapes and appearances of graphs, and what kids of situations might be modeled by different function types, and have been adding formal analysis of each family with each new unit. Starting with this big picture has given students a framework to fit each family into – they are connecting what is similar and what is different as they dive into each new kind of function.

It has been amazing to see – we have just gotten into trigonometry, and by the time we got to the sine function, kids were so comfortable with shifting graphs around the plane that I didn’t need to do any explicit instruction – they knew to play with the constants to get their graphs to shift in different ways, and with very little prompting from me, they argued out the differences between period and amplitude shifts.

I am excited to see how these understandings will transfer to the Desmos Drawing project this year. Last year’s students set a pretty high bar, but this year’s 10^{th} graders are already demonstrating a deeper understanding – and 3 months earlier. Stay tuned!