## Great Classroom Action

David Cox comes up with a sharp way to simulate the locker problem.

Geoff Krall turns a snow day (still cleaning out the backlog here!) into an estimation task for students and Facebook friends alike:

Want an easy way to build buy in? Have kids make predictions on something and make sure it takes a long time for them to see if they’re right. Like I said, our delay was a couple hours and this pretty much took up the entire time.

Nat Highstein cross-pollinates disease with probability and shares the lesson plan:

And one has … the dreaded Disease Z.

Students must identify who has The Dreaded Disease Z, as it is highly contagious – and fatal! If the infected person boards the ship with everyone else, they are all doomed.

The only way to identify each person’s health is through blood testing; a bag for each person has representative chips for their blood levels (per chart included below). I used color tiles in brown paper bags for this, and let students take 40 “blood samples.” With 40 chances, students had to be strategic about which bags to sample from.

Marshall Thompson uses math to corral his toddler.

What if I cut it into two 2 ft x 8 ft pieces and zip-tied them together? I’ll bend them into a circle with a 16 foot circumference. How much bigger or smaller than the play yard would it be? Would I need another sheet to make it big enough?