My mental block is a brain injury that went undiagnosed until I was 30. I can't really hold more than two numbers in my head at a time. I struggled through math in school because it was lecture based, and the books were written to accompany a lecture.

I can learn math fairly well if I have the right written material and the right direction. However, I do not retain math skills: without active practice, I revert back to "how do fractions work?"

For example, I did extremely well in a college algebra course that was partially online (combined with Khan Academy to catch up). I could do my tests perfectly in pen, much to the amusement of the assistants. I could make connections and see the implications and applications of the math. Roughly three to six months later, I was back to forgetting fractions.

I can't learn these things over time, but I can learn them all at once. I'm collecting resources for my next math adventure.