Hello Ajay,

Basic eligibility criteria for bsc maths is to pass 10+2 with science stream and to score 50% marks as aggregate. Some university takes admission on the basis of marks scored in 12th class. And some takes entrance exam for admission. 

Well if you give entrance exam and gwt admissions than your percentage will not affect your admissions. For msc marks scored in graduations are matters most. 

All the best.