What should I do to clear my basic maths for CAT preparation?

It depends on your target colleges. If your goal is a top IIM, retaking and improving accuracy and section strategy may help. If your expected percentile fits your shortlist of colleges, you may choose to proceed with admissions and keep other exams as backup.

At this range, candidates typically look at mid-tier B-schools and some newer IIMs depending on category and profile.

A raw score is the marks earned by candidates after considering correct and incorrect answers (+3, -1 for MCQs). Percentile compares your normalised performance with other candidates.

It is difficult but not impossible. Calls depend on category, academic record, work experience, diversity criteria and each IIM's yearly cutoff. Candidates in reserved categories or with strong profiles may receive calls from some newer IIMs.

65 marks in CAT exam is a decent, above-average score. However, It is not high enough for most older IIMs, but it can open options at other well-regarded B-schools.