The questions that come in the OIR Test of SSB in NDA are generally based on the topic of Logical and Reasoning Skills. These are Maths-based questions that are picked from the verbal and non-verbal syllabus. Some of the topics are the problem of cube and dice, visualizing patterns, jumbled words, coding-decoding, figure matrix, odd one out, logical venn diagram, reconstruction test, paper cutting, problem on rank, one word substitution, etc. Students can refer to various reference books to build their concepts.