Hey Nidhi,

For the part of mathematics i would suggest when will be doing your JEE mains syllabus or the modules.Then at that along with solving practise material do complete or solve your NCERT Question.By this you can prepare for the boards also

Also i would suggest that one or two month before the boards exam you should take out the time of atleast one week and solve the 10 previous years paper of your respective board.This step would increase your chances of getting 90+ in boards

Good Luck

jee main is multiple choice based exam. where you have show your talent within time period.

according to subjectwise you have to manage time to solving qouestions.

those subject is easier for you  that slove first, so time will spend less on that subject.

come to your math - go first of all formulae, exceptional case in mathematics, as well as practice solving problems.