Similarities and Differences — Study Notes

Overview

Similarities and Differences is a core reasoning topic in SSC GD that tests your ability to identify what items share in common and what makes one item distinct from a group. These questions appear in two main forms: finding the odd one out (differences) or grouping similar items together (similarities). The examiner wants to see whether you can spot patterns based on categories like meaning, spelling patterns, numerical properties, position in a series, or visual characteristics.

Typically, you'll see 3–5 questions from this area in the General Intelligence and Reasoning section. The difficulty is moderate, but speed matters — these are accuracy-builders if you master the pattern-recognition technique. Success here requires systematic elimination: compare items two at a time, identify the common thread, then spot the outlier. Most errors happen when students rush and miss subtle differences in category or meaning.

This topic overlaps slightly with Classification questions, but the focus here is narrower: you're explicitly asked "which is different?" or "which three are similar?" Master the common categories — synonyms, antonyms, word types, number properties, and logical groupings — and you'll handle most variations confidently.

Key Concepts

• **Odd One Out principle**: In a set of four or five items, three or four share a common property while one does not. Your job is to identify the misfit.

• **Similarity grouping**: Sometimes you must identify which items belong together based on a shared trait — meaning, function, category, or mathematical property.

• **Category-based logic**: Items can be grouped by semantic meaning (all are fruits), grammatical type (all are verbs), numerical properties (all are prime numbers), or positional patterns (all are vowels).

• **Verbal vs. non-verbal formats**: Verbal questions use words and require vocabulary knowledge; non-verbal use letters, numbers, or figures and test logical or arithmetic reasoning.

• **Elimination technique**: Compare each item against the others. The moment three items share a trait that the fourth lacks, you've found your answer.

• **Multiple valid groupings**: Occasionally items can be grouped in more than one way, but the exam always has one intended pattern that three or four items follow clearly.

Formulas / Key Facts

1. **Common categories for word-based questions**: Synonyms, antonyms, parts of speech (noun/verb/adjective), living vs. non-living, abstract vs. concrete, professions, animals, plants, places.

2. **Common categories for number-based questions**: Even/odd, prime/composite, perfect squares, perfect cubes, multiples of a number, divisibility rules, single-digit vs. multi-digit.

3. **Common categories for letter-based questions**: Vowels vs. consonants, position in alphabet (first half vs. second half), number of letters, alphabetical order.

4. **Pair/group relationships**: All items except one may represent tools, musical instruments, units of measurement, currencies, or chemical elements.

5. **Spelling and structure**: Words may differ by prefix/suffix presence, number of syllables, or origin (Sanskrit vs. Persian words in Hindi).

6. **Logical opposites**: Three items may be opposites of a concept while one is not (e.g., three antonyms of "hot" and one synonym).

7. **Functional grouping**: Items may share a purpose — all are writing instruments except one which is a cutting tool.

8. **Negative phrasing**: Watch questions asking "which is NOT similar?" — you must find the one that matches the others differently.

Worked Examples

**Example 1 (Word-based)**: Find the odd one out: (a) Rose (b) Lotus (c) Marigold (d) Cabbage **Solution**: Rose, Lotus, and Marigold are all flowers. Cabbage is a vegetable. Answer: **(d) Cabbage**.

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**Example 2 (Number-based)**: Find the odd one out: (a) 17 (b) 23 (c) 29 (d) 33 **Solution**: Check each number for primality. 17 is prime (only divisors 1, 17). 23 is prime (only divisors 1, 23). 29 is prime (only divisors 1, 29). 33 = 3 × 11, so it is composite. Three are prime, one is composite. Answer: **(d) 33**.

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**Example 3 (Letter-based)**: Find the odd one out: (a) B (b) D (c) F (d) G **Solution**: Look at position in alphabet. B = 2nd, D = 4th, F = 6th, G = 7th. The first three are at even positions; G is at an odd position. Answer: **(d) G**.

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**Example 4 (Mixed category)**: Find the odd one out: (a) Doctor (b) Engineer (c) Teacher (d) Hospital **Solution**: Doctor, Engineer, and Teacher are all professions (people). Hospital is a place, not a person. Answer: **(d) Hospital**.

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**Example 5 (Similarity grouping)**: Which three of the following are similar? (a) Square (b) Rectangle (c) Circle (d) Triangle **Solution**: Square, Rectangle, and Circle can all be described by area formulas involving sides or radius, but more directly: Square, Rectangle, and Triangle are all polygons (straight sides). Circle has a curved boundary. The three similar items are Square, Rectangle, Triangle. Answer: **(a), (b), (d)** are similar; (c) is different.

Common Mistakes

• **Rushing without checking all items**: Students pick the first item that seems different without verifying the pattern across all options. Always confirm that three items truly share a property before finalising the odd one out.

• **Confusing category levels**: Mixing broad and narrow categories. For example, treating "fruit" and "mango" as both odd when three items are vegetables. Always operate at the same level of classification.

• **Ignoring numerical properties**: In number questions, students focus only on size (largest/smallest) and miss properties like even/odd, prime/composite, or perfect square status. Check multiple mathematical traits.

• **Overlooking spelling or structure**: In letter-based questions, students forget to check alphabet position, vowel/consonant status, or uppercase/lowercase patterns. Systematically test each criterion.

• **Assuming verbal meaning only**: Some word questions hinge on grammatical type (noun vs. verb) or spelling patterns, not meaning. If meaning-based logic fails, switch to grammar or structure analysis.

Quick Reference

• **Odd one out = find the item that does NOT share the common property of the other three.**
• **For words: check meaning, grammar, category, function and origin.**
• **For numbers: test even/odd, prime/composite, divisibility, squares/cubes.**
• **For letters: verify position in alphabet, vowel/consonant, or sequence pattern.**
• **Compare systematically: item 1 vs. 2, then 1 vs. 3, then 1 vs. 4 to spot the pattern.**
• **Three-match rule: once three items share a clear trait, the fourth is the answer.**