Description: GeoGebra is free and open-source dynamic mathematics software for all levels of education. It combines geometry, algebra, spreadsheets, graphing, statistics and calculus in one easy-to-use package. It can be used to teach math from elementary through university level.
Type: software
Pricing: Open Source
Description: Wikipedia is a free, online encyclopedia written and maintained by a community of volunteers around the world. It contains over 50 million articles in hundreds of languages.
Type: software