Classification: Odd One Out in Words, Numbers, Letters and Figures
Classification: Odd One Out in Words, Numbers, Letters and Figures
In classification, three items share a property and one does not. The skill is to find the most specific property that exactly three share. Check categories for words, number properties (prime, square, cube, divisibility) for numbers, and letter gaps for clusters. If two different properties each single out an item, choose the one that leaves the other three most closely alike.
1. Property Checklist
| Items | Check in this order |
|---|---|
| Words | Category (fruit, flower, planet), function (stringed or percussion), habitat, part-whole, spelling features |
| Numbers | Odd or even, prime, perfect square, perfect cube, divisibility, digit sum |
| Number pairs or triads | One rule linking the numbers (n², n³, n × k) |
| Letter clusters | Gaps between letter positions, opposite letters, vowels |
| Figures | Number of sides, lines, dots, shading, symmetry |
Primes to 50: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47
Cubes: 8, 27, 64, 125, 216, 343, 512, 729, 1000
Letter gaps: write positions under each cluster and read the differences
✗ 33 looks prime | ✓ 33 = 3 × 11; test divisibility by 3, 7 and 11
✗ Tabla, sitar, sarod and veena are all Indian, so there is no odd one | ✓ Group by type: sitar, sarod and veena are stringed; the tabla (percussion) is odd
हिंदी नोट: वर्गीकरण में ऐसा गुण खोजिए जो ठीक तीन में हो और एक में न हो। शब्दों में श्रेणी, संख्याओं में अभाज्य-वर्ग-घन, और अक्षर-समूहों में स्थानों के अंतर देखिए।
Exam Pointer: Verified NTPC pattern: letter clusters where one breaks the gap pattern (January and April 2021 CBT-1). Word, number, number-pair and figure odd-one-out questions had no verified NTPC shift in our check and are tagged syllabus-based.
Pariksha Pattern: Every Way NTPC Asks This Topic
Pattern 1: Words
[Pattern: syllabus-based, PYQ-style]
EXAM LEVEL
Q. Find the odd one out: Rose, Lily, Jasmine, Potato.
Rose, lily and jasmine are flowers; the potato is a vegetable.
Answer: Potato
EXAMATLAS LEVEL
Q. Find the odd one out: Tabla, Sitar, Sarod, Veena.
Sitar, sarod and veena are stringed instruments; the tabla is a percussion instrument. (All four are Indian, so origin does not separate them.)
Answer: Tabla
Pattern 2: Numbers
[Pattern: syllabus-based, PYQ-style]
EXAM LEVEL
Q. Find the odd one out: 17, 23, 29, 33, 37.
All are prime except 33 = 3 × 11.
Answer: 33
EXAMATLAS LEVEL
Q. Find the odd one out: 64, 125, 216, 324, 343.
64, 125, 216 and 343 are cubes of 4, 5, 6 and 7. 324 is 18², not a cube.
Answer: 324
Pattern 3: Letter clusters
[PYQ: NTPC CBT-1 4-Jan-2021 Shift-1 | NTPC CBT-1 7-Apr-2021 Shift-2]
EXAM LEVEL
Q. Find the odd one out: ACE, BDF, GIK, MOR.
Gaps: ACE, BDF and GIK move +2, +2. MOR moves +2, +3.
Answer: MOR
EXAMATLAS LEVEL
Q. Find the odd one out: DFEH, KMLO, PRQT, TVUW.
Gaps for DFEH (4, 6, 5, 8), KMLO and PRQT are +2, −1, +3. TVUW (20, 22, 21, 23) ends with +2.
Answer: TVUW
Pattern 4: Number pairs and triads
[Pattern: syllabus-based, PYQ-style]
EXAM LEVEL
Q. Find the odd pair: (3, 9), (5, 25), (7, 49), (8, 56).
In three pairs the second number is the square of the first; 8² = 64, not 56.
Answer: (8, 56)
EXAMATLAS LEVEL
Q. Find the odd triad: (2, 8, 4), (3, 27, 9), (4, 64, 16), (5, 100, 25).
In each triad the second number is the cube and the third the square of the first. For 5, the cube is 125, not 100.
Answer: (5, 100, 25)
Pattern 5: Figures
[Pattern: syllabus-based, PYQ-style]
EXAM LEVEL
Q. Find the odd one out: square, rectangle, rhombus, triangle.
The first three have four sides; the triangle has three.
Answer: Triangle
EXAMATLAS LEVEL
Q. Four figures are a triangle with 3 dots inside, a square with 4 dots, a pentagon with 5 dots and a hexagon with 5 dots. Which is the odd one out?
In three figures the number of dots equals the number of sides. The hexagon has 6 sides but 5 dots.
Answer: The hexagon with 5 dots
60-Second Revision
- Find the most specific property shared by exactly three.
- Numbers: prime, square, cube, divisibility.
- Letter clusters: write the positions and compare the gaps.
- Pairs and triads: one rule must link every set but one.
Next Step: Classification done. Practise odd-one-out sets in the ExamAtlas RRB NTPC 2026 mock tests; write letter positions or number properties under each option before choosing.