It is possible to restart math and take it to the limit, so to speak. Find an algebra book with lots of problems and answers, and work every problem in the book. This will take some time, but try to do at least one problem a day, or a dozen if there is time, or even more when the problems are really simple. You will find you can handle numbers a lot better as you work the problems. Then get a good, thick analytical geometry and calculus book and repeat. Every problem in the book. That will pretty much do it. Then DiffEq, real analysis, linear, complex analysis, will take some work but won't be all that bad. Statistics will still be highly annoying. Then, you're done and can get into Riemannian space and cosmology if you like. Just do the algebra problems for now. Be advised that most elementary math texts are next to useless, but there are some good ones, so don't despair if the first algebra text you pick up seems crazy.
That might just do the trick. I found that I had no problems completing my homework (often getting 100%), but by the time we got to a quiz on the material, I would mess it all up. I never got to spend enough time mastering the fundamentals. Since to really understand math, you have to be competent in the prior material, well...let's just say it's easy to fall behind in that scenario.
I bought an algebra textbook a couple of years ago, but I've been too sidetracked having babies to sit down and try to learn it. Mr. Ex could help me, easily...he's on par with my uncle, math-wise.
Just don't ask him to spell! LOL
My wife, who didn't go past college algebra, recently bought a 1,200 page calculus textbook so she can work through it in her spare time, just for the sake of learning.
I love that woman!