Maxima - Maxima is a fairly complete computer algebra system written in Lisp with an emphasis on symbolic computation.
QtOctave - QtOctave: a front-end for Octave/un Front-End para Octave
SMath Studio - Tiny, powerful, free mathematical program with WYSIWYG editor and complete units of measurements support.
GNU Octave - GNU Octave is a programming language for scientific computing.
HOPEX - HOPEX is an integrated software solution to help drive business and IT transformation.
WIRIS cas - WIRIS cas is a web-based program for mathematical calculations.