Not personally, but I know a fellow back in NC that can't do arithmatic. I mean, he has to add single digit numbers on his fingers. Yet, this same guy can solve calc. and(I think) diff. equations in his head without much effort.
Edit: I'm still an ignorant pre-college jerk so I have yet to learn the 'high end, proper' methods, myself. Homeschool was great for learning computer tech, biology, literature, etc... but math is something I had trouble learning out of a book.
