Doing Math Academy right now and I'd say it's working well.
https://www.mathacademy.com/
I just started with Math Foundations 1 and relearning from the beginning :)
I kept at mathacademy for about 6-8 months and completed Foundations 1, which was mostly a review of things I'd forgotten. Once I got to Foundations 2 and started regularly failing quizzes, I had to let it go. In my opinion, the pedagogy of "learn this one method to deal with this one problem type, we'll teach you why it works later" is great for young learners and their sponge-like memory, but I'm well into middle age and my memory is shot. I failed quizzes because I forgot the rote method for the solutions, even though I mechanically understood the method and had completed several problems just like it. Taking copious notes might have helped, but there are only so many hours in the day and flipping through notes during timed quizzes is tough.
Not saying don't try it, definitely do (especially if your memory's still sharp), but if you start failing, don't be too hard on yourself.
