TED-Ed
Can You Solve the Dark Coin Riddle?
You're trapped in a dark castle with a pile of gold coins that a wizard will only allow you to leave with if you can solve his riddle. Math learners solve the riddle of the dark coin with the help of an engaging instructional video.
Khan Academy
Factoring Sum of Cubes, Polynomial and Rational Functions, Algebra II
Here is a special form of a sum of cubes problem, where students use algebraic multiplication to rewrite each term in expanded form. Sal gives an example before solving the problem to show the process that he will use to determine the...
Khan Academy
Averages, Linear Equations, Algebra I
Sal instructs the class on calculating an average using a real-life example of exam scores. He further demonstrates how to calculate what future scores would be needed to attain the desired average score by the end of the term.
Curated OER
What's a Half-Plane?
When you graph an inequality on the coordinate plane you will get two half-planes. The line itself is called the boundary line. One of the halves is called the closed half-plane and the other half is called the open half-plane. How do...