https://www.anaconda.com/ - For doing data science, or working in STEM (Science, Technology, Engineering, Math) the Anaconda distribution is the easiest (and free) way to get started. In addition to the Python and R programming languages, it has a full suite of...
www.libreoffice.org - Open source office suite of programs: document editor, spreadsheet, presentations, math formulas, database, diagram and drawing applications.