Most of the maths in finance is 2U/3U level + statistics. If you understood basic calculus, series, probability and linear functions in high school then you should be fine. A lot of the new stuff like linear algebra/matrices, partial derivatives, optimisation and statistics will also be covered during the lectures but these new concepts are based on the existing concepts from high school.
Most of the time you are given the formulas that lecturers seem to pull out of nowhere to substitute in. However, keep in mind that there is a very strong mathematical framework in which these formulas are derived from which most lecturers do not cover. In essence, the finance you do at undergraduate level is a watered down version (i.e. most of the difficult mathematics removed) of the real finance in the academic world (which has very complex mathematical and statistical concepts).