genius (mathematics tool and the GEL language)

Genius is a general purpose calculator program similiar
in some aspects to BC, Matlab, Maple or Mathematica. It 
is useful both as a simple calculator and as a research 
or educational tool. The syntax is very intuitive and 
is designed to mimic how mathematics is usually written.

If you would like the GUI interface as well, it requires
libgnomeui, gtksourceview and vte2.  If you have these dependencies, 
pass the variable of GNOME=YES (or anything that isn't NO ;)