Number Series

Odd Man Out Series

One of the most dreaded questions in the quantitative aptitude exams of all banking and competitive exams is the odd man out series questions. This is because to answer such questions students must follow only reasoning powers and logic, there are no formulas or equations to help you out. However, you can keep a few pointers in mind. Let us take a look at the Odd Man Out Series and some examples.

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Odd Man Out Series

Odd Man Out Series

On the surface of it, these Odd Man Out Series questions seem easy enough. You are given five options, and the student simply has to find the odd one out from the given set of options. However, these questions can get quite complex and often confuse the candidates.

Two things to keep in mind when solving such questions. You must thoroughly reason your answer before marking it. Make sure the answer follows basic reasoning and sound logic. Recheck your logic before finally marking the answer.

However, the candidate must also ensure that they do not overthink or overanalyze the answer. This may lead to further unnecessary confusion. Time is precious in these exams and no extra time must be wasted on overthinking.

Generally, in banking exams, there are three types of such Odd Man Out Series questions. Let us take a brief look at these three types of questions with some examples.

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1] Alphabets

Here students have to find the odd one out from a group of options containing a single alphabet or groups of alphabets. While solving such questions there are certain things a candidate must keep in mind. Here is a list of some such important pointers,

  • Might be useful if the candidates knew the place value of alphabets. It is even better if these place values are memorized, so the candidate does not waste precious time during the exam. So A is 1 and Z is 26, and of course everything in between.
  • Be clear about vowels and consonants
  • mirror images of the alphabets
  • water images of the alphabets
  • alphabetical order
  • the gap between given alphabets

Solved Examples 

Q: Find the odd one out

  1. A
  2. B
  3. C
  4. D

Ans: The odd one out is A. It is the only vowel, all others are consonants.

Q: Find the odd one out

  1. A
  2. E
  3. D
  4. H
  5. G

Ans: Answer is option D. H is the only mirror image alphabet in the list

Q: Find the odd one out

  1. ABC
  2. BCD
  3. CDE
  4. DEF
  5. EFG

Ans: The answer is B. Only group of alphabets without a vowel.

2] Numbers

Here the candidate must find the odd man out from a series of numbers. These numbers can be single digit numbers, in which case the solution tends to be fairly easy. However, when the numbers are bigger, it does get increasingly more difficult to pick the odd one out. Some guidelines you can follow are,

  • See if there is any obvious relation in those numbers
  • Next check if one specific number is in some way related to all the other numbers.
  • Check for squares and cubes of the numbers
  • Try other mathematical possibilities like divisibility by the same number, or multiples of the same number etc.
  • Sometimes, there is interrelation between the digits of the number rather than the number itself. Your last step should be to check for this.


Q: Find the odd one out

  1. 13
  2. 23
  3. 33
  4. 43

Ans: The correct answer is option C. All other are prime numbers

Q: Find the odd one out

  1. 121
  2. 253
  3. 286
  4. 372
  5. 473

Ans: The answer is D. In all other numbers, the sum of the first and last digit equals the middle digit. 1+1 =2, 2+5=3 and so on, except option D.

3] Words

Over here the logic is simple enough. Find the word that is the odd one out by applying basic reasoning skills.


Q: Find the odd one out

  1. Red
  2. Blue
  3. Yellow
  4. Green

Ans: Answer is D. All other are primary colors.

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24 responses to “Missing Number Series”

  1. anmol says:


  2. pavan kalyan says:

    1 5 20 ???

  3. Honey says:

    16,4,68,12,?,4,30,1,9 plz reply i need it

  4. Ayushi shukla says:


  5. Sneha says:


    • abcd says:

      I think
      Answer. 15
      In series of odd numbers (4, 5,9,10,14) there is addition of 1 and 4 alternately.
      And in series of even numbers (5, 7,13,?) There is addition of 2 and 6 alternately.

  6. Janu says:

    Find missing teams-1,5,14,?,44

  7. Robin rathi says:

    Find the missing number of this series

    Options 1. 12
    2. 18
    3. 25
    4. 30
    5. none this above

  8. Rohith says:


  9. Paulo says:

    ____,360,000,000,____, 389,000,000,____, 420,000,000

  10. Sune Pedersen says:

    37 52 93 75 29 ? what is the math behind this

  11. Sonali sahu says:

    2,1,0,-3,-24,? Find the next number

  12. Upper line 3 5 8 mid line 6 10 32 lower line 9 ? 50 me missing no. Kya h

  13. Akash says:

    94 101 115 136 164 ?

  14. Lokesh says:

    QID : 426 – In the following question, select the
    missing number from the given alternatives.
    41, 83, 167, 335, 671, ?
    1) 1297
    2) 1343
    3) 1447
    4) 1661

  15. Shriya Nimje says:


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