Desmos. If you’re a math teacher and you don’t know about it, stop reading this and go to their website now.
It took me a long time to even think of Desmos as one of “my favorites” because it’s so integral and every-day in my math classes that I guess I’ve started taking it for granted. I forget the days when TI button mashing ruled the day.
Here are a few things I appreciate about Desmos.
Browser Based & Free
The fact that students can access these from any computer with internet, or install the app and have them without internet access is incredible.
I have a class set of iPads, but increasingly students are asking to use their own phones. I point out to them that their eyes are going to go bad, but many of them have become proficient at using the tiny screens.
I am increasingly using the “share this graph” feature. A student will create an awesome graph and instead of just presenting with the projector, all the students in the class are interacting with their own version of the graph on their device. Or I’ll create a graph (usually a table that I don’t want to waste class time having students type in the data points) and share it quickly with the whole class. It’s great!
Nothing beats building intuition with function transformations like having students move the sliders to manipulate the values. Before Desmos, I used Geogebra, but I spent a lot of class time showing students how to make sliders–it was not nearly as streamlined and intuitive as in Desmos.
Activities & Activity Builder
I was a huge fan of Function Carnival, Penny Circle, and Central Park when they first came out. I even had my students do these, even though we weren’t exactly on those topics when each activity came out (it was review, okay?). Now Desmos has Polygraph and, the latest that I’ve yet to try with my class, Marbleslides, each excellent activities.
But I think the best thing that Desmos has done in this area is the Activity Builder. I haven’t had enough time to dig in and create activities, but the possibilities are endless. And no need to reinvent the wheel–activities that other teachers have created are available for you to see, too! Holy smokes!
To access all these cool things, go to teacher.desmos.com. I haven’t even started talking about the awesome teacher-view for when all your students are working on these activities.
And So Much More
It would take me way too long to mention all the incredible things that Desmos can do and is doing. And they’re constantly improving things. They respond quickly to feedback, both in communication and by doing the thing you asked for within Desmos.
Thank you, Desmos!
 There’s a huge bank of polygraphs since people can make their own!
 To list a few: recognizing function notation, derivatives, inserting images,intuitive click-on-the-point to find the intersection or x & y-intercept, domain & range restrictions, lists, click & drag points, regressions for any equation, implicit function, colors!, labeling axes, easy animation, and converting equations to tables. I’m sure I forgot ~90% of the features that I like.