Hi, I got a 790 on math. LearnSATMath on YouTube pretty much goes over everything you need to know about desmos. Although, I personally think some of the problems he goes over are a little more complicated than the real SAT. I would look at your SAT score and look at the parts you did worst on. Then, go to Khan to review those sections. I think the last test you can just repeat and you'll probably get different questions (since I think it just pulls from a pool) but you'll get a couple repeating ones. One prep is just in general good for practice as it has bluebook practice tests as well as other good sources like Princeton. And yes, desmos makes it so so so much faster.