general SAGE URL: <http://www.sagemath.org/>

Complete Source Code (With All Dependencies!): <http://www.sagemath.org/dist/src/index.html>

Quotes from the SAGE Web site:

Use an Open Source Alternative

By using SAGE you help to support a viable open source alternative to Magma, Maple, Mathematica, and MATLAB. SAGE includes many high-quality open source math packages.

Use a Standard Programming Language

You work with SAGE using the highly regarded scripting language Python instead of an obscure language designed for a particular mathematics program. You can write programs that combine serious mathematics with anything else.

Create Notebooks with your Web Browser

Use SAGE from your web browser, which connects either to a program running on your computer, or a program running elsewhere. With the SAGE notebook you can create embedded graphics, beautifully typeset mathematical expressions, add and delete input, and start up and interrupt multiple calculations.

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