GeoGebra is a dynamic mathematics software for all levels of education that brings together geometry, algebra, spreadsheets, graphing, statistics and calculus in one easy-to-use package. 

Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. 

Desmos is a free suite of math software tools, including the renowned Desmos Graphing Calculator and Scientific Calculator, that are used annually by over 40 million teachers and students around the world.