I was embarrassed to fail calculus twice and still pursue a finance degree which required differential calculus on a daily basis. Nothing made sense to me until I read the common sense guide to both diff. and integr. calculus. My paperback version got do dog-eared that I bought five copies of the new Gardner hardcover edition.I got that finance degree and I handle complex algorithms now. They call math geeks who handle financial math and computers programs, "quants."