GNU Octave is a high-level language, primarily intended for numerical computations. It provides a convenient command-line interface (CLI) for solving linear and nonlinear problems numerically, and for performing other numerical experiments using a language that is mostly compatible with MATLAB.
Apache OpenOffice is an open-source office productivity software suite. The applications include:
Apache OpenOffice is available for download here. OpenOffice may require java for some applications.
Physlet Physics are free physics applets and it’s free for non-commercial use. It’s made from the same team that makes Open Source Physics Project. Over 2,00 individual exercises have been created on Physlet. The applets create simple graphics to demonstrate the salient features of physical phenomena. Physlet Physics runs on Windows, Mac, and Linux devices.