I'd always get C-'s (low 70s) in math. I found math to just be a bunch of numbers, and I longed for a historical text to it. If we spent just as much time studying the people behind the numbers, I probably would be better at math (in other words, teach math like you do biology).
My grades suddenly became B's mid 80s when I took geometry; I can visualize degrees and angles rather easily.
But I forgot all of the formulas in geometry, so I'm rather useless.
The main fault to my math education was imperial units. For some reason math and distance started to make sense the minute after I crossed the border and used the metric system.