Reasoning and Mental Ability
Question families
Prepare number and letter series, analogies, classification, coding-decoding, blood relations, direction sense, ranking, syllogism, seating arrangement, puzzles, clocks and calendars, dice, mirror images, paper folding and embedded figures. Convert words into a diagram: a family tree, a direction map, or a row or circle layout. For coding, compare letter positions and test shifts such as +1, -1, reversal, or word-to-number patterns.
Traps
In blood relations, do not assume gender from a name; use the exact relationship words. In direction sense, left and right depend on the direction a person faces, so draw axes and rotate carefully. In syllogism, some does not imply all; a conclusion must be true in every possible diagram. In series, check first and second differences and alternating patterns. For calendars, an ordinary year shifts the day by one and a leap year by two.
Worked example
Find the next term: 2, 6, 12, 20, 30, ?. The differences are 4, 6, 8, 10; the next difference is 12, so the answer is 42. Rule of thumb: write first differences, then second differences, before guessing a pattern.