Khan Academy - A site to learn and practice new skills. It has video resources and practice problems on all math concepts. Each student has an account through their school email account.
BrainPop! - Lots of fun videos that explain concepts. Includes quizzes. Requires a membership to view most content. Each student has an account.
Desmos - Free, online graphing calculator
IXL - Comprehensive website with lots of games and activities to reinforce learning. The site requires membership.
Math Playground: Magic Triangle - recommended by LG2019. A customizable version of the Boxed In Challenge.
Refraction - Excellent game that requires you to understand fractional relationships. Fun because you get to shoot lasers!