The NDA written has two papers — Mathematics (300 marks) and General Ability Test (600 marks). The cut-off varies, but you need both papers cleared plus a solid aggregate.
Mathematics: The syllabus roughly overlaps Class 11 and 12 CBSE Maths. Focus areas are Calculus, Vectors, 3-D Geometry and Probability. Target speed — 2 minutes per question, maximum.
GAT is where most aspirants lose or gain the edge. English (200), GK (400). Our recommendation: daily 1-hour current affairs, weekly History / Geography revision, and targeted General Science practice.
Weekly plan for a 6-month preparation: 3 days Maths, 2 days GAT, 1 day full mock, 1 day analysis + rest.
Books: NCERT (Classes 6–12) for GAT, Pathfinder CDS / NDA for reference, previous 10 years' papers mandatorily.
A point most students miss: the SSB is a 5-day personality + psychological assessment. Start reading newspapers and building communication skills now — the SSB is not something you 'prepare' for in a week.