Quant finance (let alone finance) is not math, and should not be studied as such.

Browse this excellent & concise book, which starts with a few practical problems to test your math background; if you pass, it'll take from Forwards, to Bermudan Swaptions in only about 150 pages!

Blyth, S.J. (2013), “An Introduction to Quantitative Finance”

Fun factoid - Blyth was the former head of Harvard's Endowment and Stats prof. He taught Stat-123 which was a jr level class at Harvard. He'd put on IR options trades via Bloomberg chat in the middle of his lectures in real time!