LaTeX.org

Well maybe there's some tool to make the calculations ? Or maybe theres some LateX for python to have output as LaTeX would make it and do calculations in python ?

i'm looking for a linux program similar to Mathcad.
something that will show inline equations and perform the math based on predefines variables. even more i would like it to be able to show/hide entire sections. or maybe select what calculation are to be performed based on the information provided ...