Curated OER
The Four-Color Problem: Concept and Solution
Take a walk through time, 1852 to 1994, following the mathematical history and development of the Four-Color Theorem. Learners take on the role of cartographers to study an imaginary world of countries that need to be...
Positively Autism
Travis the Train Coin Songs
Travis the Train is hauling pennies this time. Kids sing the captions as they view the face side then the back side of a shiny new penny, and then the face and back of a tarnished penny.