"GeoGebra
Free mathematics software for learning and teaching
Download
spreadsheet-view-cobweb.png
Interactive graphics, algebra and spreadsheet
From elementary school to university level
Free learning materials"
"Greenshot is a light-weight screenshot software tool for Windows with the following key features:
Create complete or partial screenshots quickly. Easily annotate, highlight or obfuscate parts of the screenshot. Send the screenshot to a file, the clipboard, a printer or as e-mail attachment."