The difference is minor, more like just for the B.S. degree holders to "feel good" about themselves.
At UC Berkeley, ALL majors out of the School of Letters and Science aware a B.A. degree; now this includes math, two to three different programs of biology, the world famous physics department, etc; now the business school gives their undergraduate business students a B.S. degree, and the College of Chemistry and College of Engineering give B.S. degrees to chemists and engineers.
Now aside from a few majors that do have a liberal arts counterpart in L&S, like chemistry, computer science, operations research, or some different engineering majors like engineering math, engineering physics, IEOR, etc, this is how it basically boils down: if you wanna be a mathematician or physicist then you ony have a BA degree.
The B.A. in chemistry is a bit more "watered down" and has a larger liberal arts component, intended for people whose career goal is not in research or academics. The B.A. in computer science has not electrical engineering courses associated to it. And there are the "engineering" science degrees that intend to train the students as engineers rather than scientists (i.e., a student in B.S. Engineering Physics ideally would join other engineers in fields like applied physics or aerospace engineering, while a student in B.A. Physics would go to graduate school for a Ph.D. in physics and write a thesis on some topic in quantum electrodynamics, etc).
Edit: I guess the point is to check with your university first to see if a B.S. in mathematics is even offered; if not then pretty much you're in this same situation as what I listed. There's a good chance that a B.S. in mathematics will probably also fall into the engineering departments and has a lot more applied aspects to it, so if you like geometry, algebra and topology all kinds of weird stuff then you might not enjoy it as much.
At UC Berkeley, ALL majors out of the School of Letters and Science aware a B.A. degree; now this includes math, two to three different programs of biology, the world famous physics department, etc; now the business school gives their undergraduate business students a B.S. degree, and the College of Chemistry and College of Engineering give B.S. degrees to chemists and engineers.
Now aside from a few majors that do have a liberal arts counterpart in L&S, like chemistry, computer science, operations research, or some different engineering majors like engineering math, engineering physics, IEOR, etc, this is how it basically boils down: if you wanna be a mathematician or physicist then you ony have a BA degree.
The B.A. in chemistry is a bit more "watered down" and has a larger liberal arts component, intended for people whose career goal is not in research or academics. The B.A. in computer science has not electrical engineering courses associated to it. And there are the "engineering" science degrees that intend to train the students as engineers rather than scientists (i.e., a student in B.S. Engineering Physics ideally would join other engineers in fields like applied physics or aerospace engineering, while a student in B.A. Physics would go to graduate school for a Ph.D. in physics and write a thesis on some topic in quantum electrodynamics, etc).
Edit: I guess the point is to check with your university first to see if a B.S. in mathematics is even offered; if not then pretty much you're in this same situation as what I listed. There's a good chance that a B.S. in mathematics will probably also fall into the engineering departments and has a lot more applied aspects to it, so if you like geometry, algebra and topology all kinds of weird stuff then you might not enjoy it as much.