Hello Astha,

First of all, you should know that B.Sc. Hons Maths is not a core professional degree. If you pursue B.Sc. in Mathematics, then you can go for M.Sc. then Ph.D. 

If you pursue B.Sc. from IISER or other Central University then there is more scope of getting placement.

After B.Sc. if you go for IIT JAM, then you can pursue M.Sc. from IITs/NITs that will boost your career.

Final words, If you pursue B.Sc. and M.Sc. from premium institute then there are scopes otherwise not that much.

Good Luck.