Friday Five for March 32

The homework notebook of a third-grader in St Paul, MN says that’s the date today, and so it shall be recorded.


We have some delightful mathematical treasures for you on this very last day—and we really mean it—of March 2016: Crickets, Alligators, Parabolas (or are they?) and Number Lines (Middle school teachers, read all the way to the end, please!)

Cricket Chirps

You think you’ve seen this application of the algebra of lines a million times in your textbook past. But we’re telling you it’s different this time. Surprising twists contained within! Do yourself a favor and run it with some students soon.

Jiminy demands it.

Population Stories

More modeling from Michael Fenton. Need we say more? But that prediction on screen 2! No way you’re getting 100% on your first try. Such great integration of geography and mathematics—each informs the other.

(NOTE: Asking Siri or Alexa is cheating unless these happen to be names of your students, but even then you should really do your own work, don’t you think?)


That picture on screen 1 of a 900-pound alligator in all its glory never gets old. Hannah Schuchhardt has given us a very very good guard against complacency while visiting the Florida wilderness. And she’s built a great modeling activity in which serious mathematics interacts with the fantastic.

Match My Curve

Melinda Lula offers this subtle but important phrasing: as closely as you can, to her challenge to students to match parabolas to a series of images. If some cannot be matched exactly, perhaps that is because THEY ARE NOT ACTUALLY PARABOLAS! (We’re looking at you, Gateway Arch…) Talk about that possibility with your students once they’ve tried their best. Then maybe send them into the world searching for other curves masquerading as parabolas.

Fractions on a Number Line

If you haven’t checked out Nathan Kraft’s work on Activity Builder in recent months, now is the time to do that! He makes wonderful combinations of mathematics and graphics, and he taps into the early adolescent mind. Here that’s with fractions, bar models, and number lines. Attention middle school teachers! Get yourselves to this activity straight away!