NumWorks - The graphing calculator that makes learning math easier.
Learney - Knowledge aggregator for developers
Paperspade - Type math easily through just English text!
eMathHelp.net - Site is created to help people learn math. Includes algebra, calculus, differential equation calculators and notes with many examples.
Kalam Labs - Twitch for Science
MathMetrics - An enhanced mathematical interactive game allow players of any age groups & skill levels to compete on an equal footing and improve their math skills.