Khan Academy is a free online system with video lessons and practice. Students can look up a topic, watch a video explain the topic, and gives practice problems for the topic.
Desmos is an online graphing system. It will give students a visual when graphing lines, functions, ordered pairs, and more. It also allows them to graph multiple formats at the same time.
IXL is a website that allows students to practice and master skills. If the student misses a question, the system will show them how to work the problem and what the correct answer is.