Hi Rohan!

NDA exam is conducted by UPSC every year, twice. The exam is conducted for admissions to the prestigious NDA for all the three services ie army, navy and Air force. This exam is conducted in two levels, first written exam which is followed by SSB. NDA exam basically includes three defence services: Army, Air force and Navy. If you wish to join Army, then candidates need to qualify 10+2 (with any subjects, even without maths). But if you wish to join Navy or air force then you need to take mathematics and physics as compulsory subjects.

Also, in exam (if you choose mathematics), then exam will also include questions from mathematics which means only basic mathematical concepts won't help you cracking the exam.

Hope I cleared your dilemma, thankyou!