Maplesoft, providers of software and services for math education, online STEM learning, and engineering

Mathcad is engineering math software that allows you to perform, analyze, and share your most vital calculations.

LaTeX is a high-quality typesetting system; it includes features designed for the production of technical and scientific documentation.

Mathematica: high-powered computation with thousands of Wolfram Language functions, natural language input, real-world data, mobile support.