I had the same problem in high school math - symbols would be defined once, then the teacher would use them constantly but never explain what they meant again.

I had the same problem in high school math - symbols would be defined once, then the teacher would use them constantly but never explain what they meant again. And the only way to find it again is to thumb through the textbook page by page because the index lists names of concepts, not the arcane runes that correspond to them. Learning to code helped my math ability greatly, now I see sigma and think "for each, add to total".