I'm pretty at Mathematics and doing that takes a lot of work. And the Mathematics books for noobs are no good. The better approach is to get a theoretical book

I'm pretty at Mathematics and doing that takes a lot of work. And the Mathematics books for noobs are no good. The better approach is to get a theoretical book, something like Spivak's Calculus or Linear Algebra by Friedberg, Insel and Spence. And then from there whenever you have difficulty with the material spread out laterally and you really start to gradually grow an understanding of mathematics. And then perhaps, one day you'll be up for Spivak's Calculus on Manifolds!