SAT Quantum in its current form contains a large library of video explanations to mathematics questions from 53 official SAT and PSAT tests (2880 videos), and 10 official SAT Math Subject tests (500 videos). Each problem from the official test is explained in a separate video where I illustrate the most efficient way to tackle the problem.
If you have any questions or suggestions please send me an email. Thank you and best wishes for your SAT preparation.
Mahendra Dabral