carlriz:

For me, the most useful math has been algebra and trigonometry. Generally for rearranging problems into a form that I can express as a program. I use it often enough that I don't normally have to look up algebra and simple trigonometry equations. In previous jobs, I've found calculus and linear algebra handy, but those were in jobs requiring modelling (milk production) and robotics. I seem to have an obsession with graphs, and frequently read articles on them, and many of my hobby projects use graph structures a good deal.

However, that's just the practical day-to-day stuff. I wish I was better at math. I think that learning math is a lot like learning LISP--you won't necessarily use it in your programming, but it helps you think about better ways to do things. I frequently wonder how often I could solve programming problems more quickly if I were familiar with more math.

While I don't use probability and statistics much, I think it's valuable to be conversant with it. It's not uncommon to get questions or tasks based on incorrect assumptions of how probabilities and statistics work--leading to wasted time and money. (Unfortunately, I can't think of any specific examples at the moment.)

...roboticus

When your only tool is a hammer, all problems look like your thumb.