Generally speaking, for Corporate Banking, Retail Banking, etc., the maths you may usually use is arithmetics. But, you may need to use it with some finance and accounting skills.
However, for investment banking, if you are in the trading front desk, advance mathematics knowledge and skill may be required especially they may need to build some finance model, etc.
I would suggest you can explore more in the kinds of banking you are interested and would like to pursue. You may determine the level of maths knowledge it is required.
Hope this helps! Good Luck!
Like Miss Tang said, it can get more complicated depending where you are. On the plus side there is a full suite of computer applications that run the numbers for you. Some offer "what if" applications so that investors can see how the investments will behave in different scenarios. There are a lot of statistics behind those applications so understanding statistics will always be helpful. Economics may actually serve better in these more complicated scenarios.