Your Pre-Pi-Day Friday Five

Good people of the Internet, are you not aware that this year’s approximation of π is marginally BETTER than last year’s? Where are the T-shirts and Facebook posts? Well it’s not too late for you to make your plans to adhere to this quirk of the American calendar notation system. We’ve got a few Desmos circle-based activities collected at the end of this week’s post.

In the meantime, we also have five new activities hot off the Des-presses.

Function Carnival, Part Deux

So you’ve had your students work on Function Carnival, and now you’re wondering what to do the next day? Well, your loyal Desmos Teaching Faculty has an answer to that question in this new activity, Function Carnival, Part Deux. If you’re studying functions, click through, have a look, and tell us what you think!

Polar Graph Exploration

Meg Craig brings us some polar playfulness in the plane. Start with base functions, and match graphs (if that’s possible…is it always possible?) Trig and precalc teachers, this one’s for you!

Graphing the Sine Function using Amplitude, Period, and Vertical Translation

Shelley Carranza

has combined the Function Carnival references with the trig functions and mashes them up into a solid sine function activity for trig and precalc students.

Wafers and Crème

If you were living under a rock in 2013, you may have missed the great kerfuffle over the actual ratio of stuf (that’s right: one f. Not a typo) in a Double Stuf Oreo to Stuf in a regular Oreo. This controversy reached its peak (as all controversies do, it seems) on Fox News, when Dan Anderson was interviewed by Sam Shepard on the matter. We are not making this up!

Well, now there’s a Desmos Activity Builder version that begins with the assumption (which is, as discussed above, possibly false) that Double Stuf Oreos are in fact doubly stufed. If they are, and if the Nutrition Facts provided by Nabisco are to be believed, then your students can determine which has more calories—a single layer of stuf, or a single wafer. Before you peek, how say you?

Equations of Circles

Finally, Lauren Olson challenges students to encircle some points in the coordinate plane, while excluding others, in a challenge with multiple correct solutions as well as solution methods.

And now…Pi Day!

That last activity provides the transition to our π day resources. The easiest thing to do (and you can do this on any day, not just ones with math-y dates!) is search “circle” at

Or if you don’t have time to sort through them all, try one of these:

- Luke Walsh’s Coordinates, Circles, and Symmetry

- Kate Nowak’s Measuring Circles

- The Desmos classic Penny Circle

- Annie Perkins’s Polygraph: Circles and Ellipses