Classification is a high-frequency SSC General Intelligence topic and a regular in banking papers, and it is unusual in rewarding a checklist over insight. Candidates who search for the rule by inspiration are slow and inconsistent; those who run a fixed sequence of tests clear each question in fifteen to twenty seconds.
Prime or composite, then perfect square, then perfect cube, then divisibility by a small number, then digit sum, then the gap to the nearest round number. Fixing the order means you never stall wondering what to try next, which is where the time actually goes.
Write the alphabet positions under each group and compute the differences within each. Three groups sharing a gap pattern and one breaking it is the commonest construction. If gaps match, check vowel and consonant placement next.
A valid rule leaves three items together and one alone. If a candidate rule splits them two and two, it is the wrong rule — discard it immediately rather than trying to argue it into working.
Occasionally two properties each single out a different item. The intended answer is nearly always the one found by the simpler and more general rule; an elaborate property that happens to fit is usually coincidence rather than design.
| Test | What it catches |
|---|---|
| Prime or composite | The commonest numeric rule of all |
| Perfect square or cube | Second commonest; check both |
| Divisible by 3, 4, 7 or 11 | Catches most remaining numeric sets |
| Digit sum or digit reversal | Used when the values are close together |
| Alphabet gap pattern | The default first test for letter groups |
| Vowel or consonant position | Letter sets where the gaps all match |
Every question below was generated by the same engine that mints the Deduce daily puzzle, and machine-proven to have exactly one correct answer before it reached this page. The walkthrough is the engine's own, step for step.
Four of these five numbers are alike in a certain way and form a group. Which number does NOT belong to that group?
Four of these five numbers are alike in a certain way and form a group. Which number does NOT belong to that group?
Four of these five numbers are alike in a certain way and form a group. Which number does NOT belong to that group?
A classification rule must isolate exactly one item. A property shared by two pairs is not the rule the question was built on, however neat it looks — move on rather than trying to justify it.
Staring at four numbers hoping the pattern appears is slow and unreliable. The checklist is quicker precisely because it does not depend on noticing anything.
One is neither prime nor composite, two is the only even prime, and zero breaks several divisibility intuitions. Sets are frequently built around exactly these edge cases.
One puzzle a day, timed on the server, with a national and state leaderboard and a streak that survives as long as you do. Practising a topic once is worth little; the aspirants who move are the ones who show up daily. See what Deduce does or read the rules first.
Start your streak free →Run a fixed checklist rather than searching for inspiration: prime or composite first, then perfect squares and cubes, then divisibility by a small number, then digit sum. Stop at the first rule that leaves exactly three items together and one alone. Most exam sets are solved by the first or second test.
Write the alphabet positions beneath each group and compute the gaps inside each one. Three groups sharing a gap pattern and one breaking it is the standard construction. If every gap matches, look at vowel placement or whether the letters are consecutive.
Prefer the simpler, more general rule. Question setters build from one clean property; an elaborate rule that happens to fit is usually coincidence. If both rules are equally simple, re-check your arithmetic, since a genuine double answer is far rarer than a slip.
They are close relatives and both are heavily tested in SSC General Intelligence. Classification asks which of four items breaks a shared rule; analogy gives a related pair and asks you to complete a second pair by the same relation. The property checklist above is the useful half of both.
Deduce is not affiliated with IBPS, SBI, SSC or RBI.