14 May


Series completion is an imperative and complex subject matter of both verbal and non-verbal reasoning. The topic remains in focus for not only SSC but also for many other competitive exams. But we stick to SSC exam only and it is a matter of concern if anyone who aspires to clear SSC is not good at solving series completion questions.

What are series completion questions?
For such questions, a series is given, this series can be numbers, alphabets or a combination of both. The series follows a certain pattern and all an aspirant has to do is recognize this tacit pattern and follow the same to complete the series. Sound simple? It is not…. Finding that hidden pattern can be a herculean task if you have not practiced it thoroughly or have certain result-oriented tips and tricks that would take you to the right pattern. Hence, here in this blog, we are sharing not only the most effective tricks for unveiling the hidden pattern but will explain their usage with examples as well.

Let’s start with some common patterns, most frequently asked in the SSC exams

a) Prime numbers – When the series provided is of prime numbers. Some of these numbers are 5, 7, 11, 13, 17, etc.

b) Squares or Cubes – When the series provided has numbers of perfect squares/cubes/ square roots or cube roots. Some examples might be – 81, 100, 121, etc. The series might have such numbers in decimal nature as well.

c) Pattern in differences – Calculated by subtracting the numbers provided in the series. This difference can either be constant or vary in some coordinated pattern.

For example – 3, 8, 13, 18, 23,?

Let’s start by calculating the difference in the series, it is 5. Hence, the number that fills the question mark would be 28.

d) Pattern in Alternate numbers – It is not difficult to find a pattern in series with alternate number/letters or even words. All you need is the focus.

For example: 2, 3, 4, 7, 6, 11, ?

In the given series, the alternate numbers in the series are incremented by 2 and 4, which is like 2+2=4, 3+4=7 and so on. Hence, the number that will fill the question mark would be 8.

Similarly, candidates can work out the solution for letter or word series.

e) Geometric series – There can be series that follow the geometric progression, which means each successive number in the series is obtained either by multiplying or by dividing the previous number with a fixed proportion. This trick brings an easy solution.

For example: 4, 20, 100, 500, ?

Here, each number is multiplied by 5 with a geometric progression, hence the number that fills the question mark would be 2500.

f) Pattern in the adjacent numbers – Then there are series that have adjacent numbers that follow a logical pattern. Let’s explain this with the following example:

Example – 2,4,12,48, ?

In this example, the first number is multiplied by 2 to get the second number and second number is multiplied by 3 to get third number and third is with 4 and so on. Hence, the number that fills the question mark would be 240.

g) Odd one out – The most commonly asked question type is ‘Odd one out’. Here, the candidate has to identify a number, letter or words for elimination.

h) Complex series – In these types of questions, the differences between numbers are dynamic rather than being fixed with a clear implementation of the logical rule.

Example: 3,8,15,24,33, ?

Here, the increment of the numbers follows a logical rule, which is +5, +7, +9 and so on. Hence, the final number will see an increment of 13, giving the answer – 46.

i) Complex arithmetic functions – In some questions, the candidates have to perform more than one operation. Such problems need regular practice sessions from a reputed SSC coaching in East Delhi because these patterns are tough to recognize and are time consuming.

Example: 4, 6, 12, 14, 28, ?

This example sees multiple operations, the first one being an addition and the very next is multiplication. Hence, to solve this series we need to increment the first number by 2 and multiply the next number by 2. Following this logic, you will end up reaching the solution, which is 30.

In this blog, we have covered almost all the patterns and the tricks that would take you to the right solution.
Good Luck!

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