Mathematics major can span economy, finance, computer and so on. There are many interdisciplinary majors in our class. So far, as long as the cross-majors are good, the non-majors are slightly worse. In fact, it doesn't matter what major you major in, mainly because you went to a good school and followed a good tutor. The level and responsible attitude of the tutor directly affected your life's work. Generally speaking, there is no problem that their professional foundation is worse than their major. Are we afraid to read more books when we study mathematics? Still afraid that the basic knowledge can't make up? The biggest drawback of cross-major may be that in the early stage of job hunting, employers may find that your major is not right. But if you study hard and make some achievements during graduate school, these problems will be solved, not to mention meeting a responsible tutor again, then find a job. Personally, I think graduate school is to be a tutor. Choosing a mentor depends not only on popularity, but also on the personal charm and sense of responsibility of the mentor. Of course, there is no channel for students who take the postgraduate entrance examination to know about the tutor, so they can only make a general inquiry. I recommend it to you. It's best to find the students he is taking now to understand the situation.

I hope it works for you. I have graduated from mathematics to engineering. Come on!