Instructional Video8:52
Curated Video

HARD Logic Puzzle - The Seemingly Impossible Counterfeit Coin Problem

6th - 11th
An evil warden holds you prisoner, but offers you a chance to earn your freedom. You are given 101 coins, of which 51 are genuine and 50 are counterfeit. Each genuine coin is identical. And each counterfeit coin is identical to a genuine...
Instructional Video4:26
Curated Video

Smartphone App Solves Common Core Test Problems

6th - 11th
PhotoMath is a pretty neat app that can solve math problems instantly. Here is the app solving some sample Common Core test questions. Links to the free app and more below... PhotoMath App (Currently free on iPhones, Android, Windows,...
Instructional Video3:07
Curated Video

Did You Know 2% Milk Actually Has 34% Fat?

6th - 11th
I have 2 percent milk with my cereal. But it's not really 2 percent milk-fat by calories--it's actually about 34 percent fat by calories. Blog post explanation...
Instructional Video14:57
Curated Video

Proving pi is irrational (using high school level calculus)

6th - 11th
I did make one big typo/mistake in the video: at 3:40 I claimed that f(x) is a polynomial with integer coefficients. I meant to write n!f(x) is a polynomial with integer coefficients. Commenter ffggddss also pointed out some other...