Classification / Odd One Out
Classification, also called Odd One Out, is an important topic of the verbal reasoning paper of ADRE Grade IV. In each question a small group of words, letters or numbers is given and the candidate has to find the single item that does not share the common property of the rest. The topic tests the power of observation, general knowledge and the ability to notice a common quality quickly. The questions are short and carry one mark each, so a well-practised candidate can collect these marks easily.
Meaning of Classification
Classification means grouping things on the basis of a common feature. When three or four items of a group share a quality such as colour, shape, use or category and one item does not, that item is the odd one out. The common property may be based on meaning, spelling, number, place, profession, or whether the thing is living or non-living. The candidate must discover the hidden rule that unites the majority of the items and then choose the item that breaks it.
Bases of Classification
- Category — fruits, vegetables, animals, birds, vehicles.
- Nature — living and non-living, natural and man-made.
- Use — tools of a trade, articles of a kitchen.
- Place — things found in a hospital or a school.
- Word property — number of letters, vowels or starting sound.
- Number property — odd and even, prime, square or cube.
Types of Odd One Out Questions
Word classification is the most common, in which a group of words is given and the odd word is based on meaning or category. Letter classification uses a group of letters or words and the odd one is found by the position, number or order of the letters. Number classification gives a set of numbers where the odd one differs in a mathematical property such as divisibility or being a perfect square. General knowledge classification draws on facts from science, history and everyday life.
Worked Examples
In the group "Rose, Lotus, Marigold, Mango", the first three are flowers while mango is a fruit, so mango is the odd one out. In "2, 4, 6, 9", all the numbers except 9 are even, so 9 is the odd one out. In the group "Chair, Table, Bed, Pen", the first three are furniture while a pen is a writing instrument, so pen is the answer. In letter classification "BD, HJ, LN, PR", each pair has one letter skipped between them, and any pair that does not follow this rule is the odd one.
How This Topic Appears in the Examination
Odd one out normally appears as three to five objective questions of one mark each. The questions are very short and can be answered in a few seconds once the common property is seen. Many questions are of a general awareness nature, so a candidate with good general knowledge has an advantage. Because the answer depends on choosing the correct common property, the candidate must be careful not to select an item that also fits another grouping.
Memory Tips
Before deciding, try to state the common property of the majority in one word or phrase. Check each item against that property in turn and notice the one that fails. Look for the simplest and most obvious property first, since the examiner usually intends an easy classification. For numbers, test even-odd, prime, square and divisibility. For words, check meaning, category, spelling and the number of letters. Practise with mixed groups so that you can shift your thinking quickly.
Common Mistakes to Avoid
- Choosing an item that can also be grouped in another way.
- Looking for a complicated rule when a simple one exists.
- Ignoring the number or letter property in numerical groups.
- Being misled by one familiar word and not checking all items.
- Rushing without first stating the common property in words.
How to Prepare This Topic
- Revise common categories such as fruits, animals and vehicles.
- Practise ten word classification sets every day.
- Learn the properties of numbers up to one hundred.
- Make a list of groups that appear often in tests.
- Time yourself so that each question takes only a few seconds.
More Solved Examples
In the group "Copper, Iron, Silver, Wood", the first three are metals while wood is not, so wood is the odd one out. In "Delhi, Mumbai, Chennai, Nepal", the first three are cities of India while Nepal is a country, so Nepal is the odd one out. In "3, 5, 7, 9", all except 9 are prime numbers, so 9 is the odd one out. In "AB, CD, EF, GH" each pair has two consecutive letters, so a pair such as "IJ" would continue the rule and any pair with a different gap would be the odd one. Always state the common property clearly before choosing.
Advanced Tips for the Exam
Try to find the property that fits three of the four items exactly, because the odd one is the item that does not share it. If more than one item seems odd, then the property you have chosen is wrong and a simpler one should be tested. For numeric groups, check prime numbers, even and odd, perfect squares and divisibility by three or four. For word groups, think of category, use, place, spelling and the number of letters or vowels. Read all four options before deciding, and never stop at the first item that looks different.
Quick Revision Checklist
- Common categories such as fruits, animals, metals and vehicles.
- Even, odd, prime and perfect square numbers.
- Living and non-living, natural and man-made things.
- Place-and-object groups such as hospital or school.
- Letter gap and vowel-count rules.
- Stating the common property before choosing the answer.
Frequently Asked Questions
What is an odd one out question?
A group of words, letters or numbers is given, and you must find the one item that does not share the common property of the other items in the group.
On what basis can items be classified?
Items can be classified by category, nature, use, place, word property or number property. The examiner picks the simplest property that fits most of the items.
How do I solve a number odd one out quickly?
Check even and odd, prime numbers, perfect squares and divisibility. In 2, 4, 6, 9 the odd one is 9 because all others are even.
What if two items seem to fit the group?
Look for the property that fits the largest number of items and leaves exactly one out. Choose the classification that is most natural and specific.
How much time should each question take?
An odd one out question should take only a few seconds. Daily practice helps you spot the common property almost instantly.