Calcbot for Apple Watch - Calculate, convert, and split tips from your wrist

GnuPlot - Gnuplot is a portable command-line driven interactive data and function plotting utility.

SpeQ Mathematics - SpeQ is a small, extensive mathematics program with a simple, intuitive interface.

Dr. Geo - Dr. Geo, a software to design & manipulate interactive geometric sketches.

Qalculate! - Qalculate! is a multiplatform multi-purpose desktop calculator.

Giac/Xcas - Free computer algebra system