M.Sc Maths

You have to appear for entrance DTU CET. There are 33 seats there must be screening. Since you have excellent academic record, it would definitely be beneficial to go for the entrance. Go to the website for course details:
http://www.dtu.ac.in/

Admission into the two year Post Graduate Programme M.Sc. In Mathematics Applied Mathematics (English Medium) is open to all citizens of India who hold a Bachelor's Degree with Mathematics as one of the elective subjects of study from any Indian University recognised by the UGC. So from above a Bachelor degree with Mathematics is mandatory here. So you are not eligible.

I think you should go with B.Sc. Statistics, because B.Sc. Data Science students have big competition with B.Tech CSE students and most of the companies prefers to select the B.Tech CSE students in place of B.Sc. Students.

Yes, you can study MSc maths after BBA.
However, I won't recommend going for it, as if you really have a passion for maths, doing other courses in maths specialization would be better for your career.
All the best.

The jobs are plenty. You may take NET for assistant professor ship or go in research sector. Actuarial Sciences is another sector, where insurance companies require data analysts. Opening in software sector are numerical analysis in computer system design, operation research, software programming, etc. Some of the companies recruiting candidates after M.Sc. Mathematics are Oracle, Microsoft, Google, etc. The candidates can find job opportunities abroad as well.

Yes, you can do B. Ed after B. Com, the minimum qualification required for entry into B.Ed course is Bachelors of Arts (BA), Bachelors of science (B. Sc) or Bachelor of Commerce (B. Com) from a recognized board/university with at least 50% marks.

Hello Yogesh
1. Research and development firms.
2. Economic research firms.
3. Market research firms and
4. Manufacturing firms. They can look for the job profiles like:
1. Quantitative risk analyst.
2. Statistician.
3. Treasury management specialist and
4. Demographer in these firms. Those who want to work in public sector can find ample opportunities in various government organizations like:
1. Defense Research and Development organisation (DRDO) and
2. Indian Space Research organisation (ISRO). Thank you.