hi,

NDA exam is conducts by union public service commission, the syllabus is includes mathematics and general ability test, for mathematics syllabus included matrices, determinants, differentiation,  Statistics and Probability, Quadratic equation etc, so follow the 11th 12th books of mathematics and regularly practice the previous years papers and short cut ways to solve,

for general ability test, part 1- english and part 2- general awareness, you may daily practice and revise grammars from any good books. for general awareness follow 10th standard books  physical science and life science and solve the mcq problems.