Basic mathematics is the foundation of many sciences, and it is also a necessary part of some social sciences, such as finance and economy. Therefore, undergraduate study of basic mathematics can not only continue the mathematical research at the graduate stage, but also be easily transferred to other majors such as science, statistics, finance, economics, etc., with a wide range, and many of them are good in Qian Jing at present.
If you work directly, as far as I know, it is not bad to go to the enterprise for development. After all, mathematics has applications in various fields (such as finance and economy mentioned above), and people usually think that the brains who study mathematics are very smart, and there won't be too many restrictions. The brand of Peking University itself is good.