GeoGebra

“GeoGebra is an interactive geometry, algebra, statistics and calculus application, intended for learning and teaching mathematics and science from primary school to university level.”
(“with the help of open-source developers and translators all over the world”)
Here is the link to the Wikipedia article on this topic.
keywords:
[Mathematics]
[education]
[instruction]
[training]
[learning]
[study]
[educators]
[interactive]
[interactivity]
[dynamic mathematics software]