Hello aspirant ,

You just need to Stick to NCERT and additionally exampler for maths. There are many core topics from class 10 also so revise them thoroughly.

You can also refer books like pathfinder from Arihant publications for your preparations.

Secondary

There are basically 2 papers in NDA examination.
Mathematics - 300 marks - 120 questions
General aptitude test - 600 marks - 150 ques.

Negative marking - 1/3 for both papers.

Criteria for selection
You need to score min 30 % in each paper .
Securing above 120 marks in Maths and 150-160 (tel:150160) marks in GAT assures clearing of both papers individually.

Since cutoff varies from year to its hard to predict final cutoff but a total score of 350 and above can assure call for SSB.

I hope this helps.
Regards
Madhur