Ntccrt is an interpreter for the Non-deterministic Timed Concurrent Constraint (ntcc) calculus and its probabilistic extension (pntcc). It allows to execute models either as a stand-alone program, as a patch in OpenMusic or as an plugin in Max/MSP or PD
GeoGebra is free and multi-platform dynamic mathematics software for learning and teaching geometry, algebra, statistics, and calculus. Download the free software at http://www.geogebra.org. Find the source code at http://www.geogebra.org/trac
Matho is a OS Independant Application and API for mathematical operations, features include curve sketching, calculus, iterative formulae, algebra solver, 2d/3d geometry and mechanical and statistical functionality.