Can I do M.Sc IT after doing B.Sc in mathematics?

Yes, you are eligible for M.Sc, but please check eligibility criteria for the institution/University, because different universities have different eligibility criteria.

M.Sc (Information Technology): Eligibility- Candidates can be eligible for admission, if they fulfill any of the following conditions: Bachelor's degree in Information Technology/ Computer Science/ Physics/Stats/Electronics or equivalent examination with at least 50% marks in aggregate from a recogn