For my computer science degree:
We were generally assumed to just know algebra, and this came up in particular in analyzing how long algorithms will take to complete, but really could appear anywhere.
Everyone took Discrete Math, which lead into a lot of other useful areas like logic, graph theory, and set theory.
For certain areas, such as graphics, Linear Algebra (the study of vectors and matrices) became fairly important.
Those are the main ones that occur to me, but math can lurk in a lot of unexpected areas. Hope this helps!