Each trick says when to use it, why it works and when it fails. Formula tricks are checked by code over their whole range.हर ट्रिक बताती है कि उसे कब इस्तेमाल करें, वह क्यों काम करती है और कब नहीं। सूत्र वाली ट्रिक्स को कोड से उनकी पूरी रेंज पर जाँचा गया है।
Exam strategyपरीक्षा रणनीतिRarely taughtकम सिखाई जाने वाली✓ Checked on 270 cases✓ 270 मामलों पर जाँची गई
The series ladder: six checks in a fixed order
Use it when:कब इस्तेमाल करें: Any number series, missing term, wrong term, or a number analogy or odd-one-out that hides a pattern.
Differences constant? (arithmetic)
Differences of differences constant? (quadratic growth)
Ratios constant? (geometric)
Each term = previous × a + b? Find a from two jumps: a = (t₃ − t₂)/(t₂ − t₁).
Near squares or cubes? Compare with n², n³ and check ± a small constant.
Split odd and even positions: two simpler series interleaved.
Stop at the first check that explains every term, then verify it on the last term too.
Why it works, and when it failsयह क्यों काम करती है, और कब नहीं
Why:क्यों: Exam setters build series from a handful of rules. Checking them from cheapest to costliest finds the rule with the least arithmetic, and step 4 turns the guess “× something + something” into a calculation.
Limits:सीमाएँ: Rare series mix two operations alternately (×2, +3, ×2, +3). If all six checks fail, try alternating operations on consecutive terms.
Solved examplesहल किए गए उदाहरण
Answers and full solutions are shown. Hide them to test yourself first.उत्तर और पूरे हल दिखाए गए हैं। पहले खुद को परखने के लिए इन्हें छिपाइए।
Example 1उदाहरण 1 · Odd one out (numbers) · Easyआसान
Find the odd one out: 77, 67, 89, 61
77
67
89
61
Answer:उत्तर:77
61, 67, 89 are prime numbers.
77 is not, so it is the odd one out.
Example 2उदाहरण 2 · Odd one out (numbers) · Mediumमध्यम
Find the odd one out: 73, 13, 51, 83
73
13
51
83
Answer:उत्तर:51
13, 83, 73 are prime numbers.
51 is not, so it is the odd one out.
Example 3उदाहरण 3 · Odd one out (numbers) · Hardकठिन
Find the odd one out: 546, 808, 286, 592
546
808
286
592
Answer:उत्तर:546
592, 286, 808 are numbers whose digits add up to 16.
546 is not (digit sum 15), so it is the odd one out.
Example 4उदाहरण 4 · Odd one out (numbers) · Mediumमध्यम
Find the odd one out: 43, 79, 21, 41
43
79
21
41
Answer:उत्तर:21
43, 79, 41 are prime numbers.
21 is not, so it is the odd one out.
Example 5उदाहरण 5 · Odd one out (numbers) · Mediumमध्यम
Find the odd one out: 41, 71, 21, 23
41
71
21
23
Answer:उत्तर:21
23, 71, 41 are prime numbers.
21 is not, so it is the odd one out.
Example 6उदाहरण 6 · Odd one out (numbers) · Mediumमध्यम
Find the odd one out: 44, 132, 120, 110
44
132
120
110
Answer:उत्तर:120
44, 132, 110 are multiples of 11.
120 is not, so it is the odd one out.
Common mistakesआम गलतियाँ
Stopping at a property that splits two to two.
Overthinking: the intended rule is usually simple.
Frequently asked questionsअक्सर पूछे जाने वाले प्रश्न
How do I find the odd one out in numbers?
Check primes, squares, cubes, multiples and digit sums until one property splits the four items three to one.
Is classification asked in SSC?
Yes, usually as several questions on numbers, letters and words.
What about word classification?
Word and letter-cluster classification is coming to this practice set.