Dear Applicant,

You can persuade your bachelor's in maths and side by side prepare for ssc cgl examination. Maths is a subject that requires utmost attention you cannot neglect it. This can be achieved only if you set a good timetable and distribute the study material well, but If you think you cant handle both of them together, than finish your graduation first than prepare for the ssc cgl examination. You can totally go with maths or btech it's up to you both are acceptable.