Most business software doesn't require more than basic algebra. As long as you know how to read math formulas and implement them in code, you can just look up most of the stuff on wikipedia.
For example, I worked on a monthly payment calculator for loans. All I needed to do was spend an hour reading http://en.wikipedia.org/wiki/Annuity_(finance_theory)#Proof and playing with the forumla on paper.
Create a function to wrap the algorithm and test the inputs and outputs. Then you spend 2 days writing code and tests for the web interface around the function. In my job most programming is plumbing with infrequent math problems that only need to be solved once in a generic fashion. Heck, if there's complex math, there's an open source library for that. (Or a contractor! Or a web service. Or a contractor writing a custom accounting system that does the heavy lifting.)
Unless you're going to be specializing heavily on a specific problems, you don't need college level math, you just need your basic high school education and access to the internet.\
Note: My high school education included a semester of statistics. I would add my discrete mathematics classes in college have been useful but not strictly necessary.