Alphabet Series

For CET Graduation 2026, the official Logical Reasoning and Mathematics block lists Alphabet Series as a distinct topic. This lesson therefore stays on alphabet movement, letter positions, missing letters, alternating rules and letter-number patterns. It should not drift into coding-decoding, seating arrangement, direction sense, dice, mirror image, paper folding or decision-making sets, because those are not the teaching target of this file. Start every question by writing the alphabet-position line: A=1, B=2, C=3, ... Z=26. Then ask three checks. Are the letters moving forward or backward? Is the gap constant, increasing, decreasing or alternating? Are two separate sequences interwoven in odd and even places? In A, C, F, J, O, the gaps are +2, +3, +4, +5, so the next letter is U. In Z, X, U, Q, the gaps are -2, -3, -4, so the next letter is L. The exam skill is not memorising many samples; it is proving one rule that explains every given term. Keep the rough-work format fixed across practice: write the given series, write the position values just below it, and write the gap row under the positions. This three-line format makes most hidden patterns visible. If the first direct gap row looks irregular, do not immediately abandon the question. Check whether the odd places and even places form two separate series, whether letters are paired with their opposite letters, and whether a number track is controlling the letter track. The rule must be economical: it should explain all terms with the least number of assumptions. A rule that works only after changing the alphabet convention, skipping an unexplained term, or using a special exception is usually not the intended CET answer. For revision, practise the same series in both directions: after finding the next term, also ask what the previous term would have been. That reverse check catches weak rules quickly.