If you're planning to have some review, whether it be over the summer or for your SAT tests (for me it's both), it's a great tool to review by.
But, let me tell you this: You must know the background information of each chapter. For example, if you know nothing of Integers, it's best if you search up and then watch the video. Each video is from 30 seconds to a minute. They review, not provide a whole lesson on how to do the concepts.