After b.tech from IIT college can I do M.Sc in Mathematics ?
Yeah! you can do the MSc in Mathematics by qualifying the IIT JAM examination through which you can take admission in IIT's and NIT's for the MSc course. Apart from this there are also some research institutes such as TIFR which accepts candidates for Integrated PhD program as well. For that you need to qualify the TIFR GS or JEST examination. You can also take admission to IIT's for integrated PhD programs as well as in IISc through IIT JAM. For IISERs and NISERs integrated phD program you can take admission on the basis of GATE/JEST. So there are numerous possibilities for you to opt if you are enthusiastic about Mathematics.
To know more about Mathematics as a career visit the link below:
https://www.careers360.com/courses/mathematics-course
I hope this answer helps. All the very best for your future endeavors!