Hello dear!
Yes your eligible to pursue MBA in HR with B.SC maths as your degree  with atleast 50% Mark's in aggregate.
Now coming to the job opportunities after MBA in HR
1. MBA In HR holders works as a part of team that forms the backbone of a company or an institute .
Career opportunities: -  MBA  HR holder may work in government and private sectors both ( depends on your interest) . You may also work in banking sectors , industries, educational institutions,  and MNCs.Also if you have interest in teaching can join B-schools as professors . If your more interested you can further carry on with research in the field also and can pursue the fellow programme in management ( FPM ) .

Job profiles for MBA in HR
The job of HR manager is challenging one !
1. HR generalist
2. Staffing Director
3.Technical recruiter
4.Director of HR training and development
5.Employee relations manager
6.Employment or placement manager
7.compensation manager
8.organisational development and change consultant

All this job profiles offer a good salary package depending on the companies

Now coming to the specialization
As you have mentioned HR with operations or HR with systems...
HR with Operations management as a dual degree is a best option as you will have a wide range of opportunities further .
Operations management is related to increase the performance of a factory or company .so combination of HR with operations will give more impact after your graduation

And one more thing I would like to add..
Along with your bachelors degree you need to be qualified in any nationalized entrance examinations such as CAT/MAT/GMAT/XAT etc.

Hope its helpful
Feel free to ask further questions regarding this !

Good luck dear!