Polynomial, matrixes, derivatives, integrals, equations or interpolation are some of the operations that can be solved using Scilab. It supports both normal and scientific calculations.
Like in any other programming language, operations in Scilab are described through the use of variables, operators, functions, flow control, etc. Its strong point is graphic generation in two and three dimensions (it is capable of creating a PostScript file from them).
If you would like to start using Scilab, you can consult a rather complete Spanish manual about this application by clicking here.