MathCrunch - Learn math stress free
SpeQ Mathematics - SpeQ is a small, extensive mathematics program with a simple, intuitive interface.
Kalam Labs - Twitch for Science
Qalculate! - Qalculate! is a multiplatform multi-purpose desktop calculator.
Code Fight Club - A fight club you can talk about. Less punching, more coding.
NoteCalc - Browser-based notepad built for math calculations.