RRB Group D · Bite-size lessons

Classification

About 5 min · General Intelligence and Reasoning · English

Time worked out from the lesson's 296 words at 150 words a minute, plus a minute for each question.

The fundamental principle is simple: you are given four or five items (words, numbers, or figures), and your task is to identify which one does not belong to the group based on a common property shared by the others.

Key ideas

• Homogeneity Principle: Three or four items share a common characteristic (category, property, or pattern), while one item violates this shared property. Your task is to identify the odd one out.
• Multiple Classification Bases: Words can be grouped by category (fruits, animals, metals), grammatical form (verbs, nouns), or conceptual relationship (capital cities, scientists). Always choose the most obvious grouping.
• Number Properties: Numbers may be classified by mathematical properties such as prime/composite, even/odd, perfect squares/cubes, multiples of a specific number, or arithmetic relationships between digits.
• Figure Classification: Visual patterns may involve shape types (polygons, circles), symmetry (axis of symmetry, rotational symmetry), number of elements (sides, angles, enclosed regions), or orientation and shading.
• Degree of Oddness: Sometimes multiple items appear different, but one is "most different." Choose the item that violates the most fundamental shared property.

Quick reference

• Three-item rule: If you can find a common property linking any three items, the fourth is the odd one.
• Word classification priorities: Category membership > conceptual relationship > grammatical form.
• Number quick checks: Prime/composite first, then even/odd, then perfect powers, then divisibility.
• Figure analysis sequence: Count elements (sides, shapes) → check symmetry → examine internal details → verify orientation.
• When stuck: Eliminate options; if three items clearly share something, the fourth is your answer regardless of why.

Check yourself: 3 questions

This lesson is cut from the topic's note, not rewritten. Fact-checked on 21 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain. The questions are from Shishya's validated question bank.

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