I am curious about the possibility of pursuing pure mathematics at the graduate level while only having a minor in math from undergrad. Can this be done? Currently, I am an engineering student, but I am not all that enthusiastic about what I'm studying. It's not that I dislike engineering, I just enjoy my math courses a lot more. I find learning mathematics enlightening and do not want to shut the door on a possible career in it. So is a math minor a valid way of keeping my options open or will not having a BS kill my chances? If the former is possible, which upper-level courses do you recommend taking?