Khan Academy – great site to find videos, practice questions and quizzes on specific math topics. Some units even have unit tests at the end. Here is the link
Sophia Learning - another great free site to find videos, practice questions and quizzes on specific math topics. Great for extra help with the basics all the way up to Calculus 1.
Mr.Sweeney’s pbworks page – One of the best sites to find academic videos specifically covering Ontario curriculum. Courses covered include; MHF4U, MCV4U, MCR3U and MPM2D.
CEMC - University of Waterloo: The Centre for Education in mathematics & Computing features lessons, interactive activities, enrichment challenges, and unlimited opportunity for practice with feedback.
GeoGebra - free online math tools for graphing, geometry, 3D, and more