How to solve NUMBER SERIES PROBLEMS
Generally, two kinds of series are asked in the examination. One is based on numbers
and the other based on alphabets.
Step 1: Observe if there are any familiar numbers in the given series. Familiar numbers
are PRIME NUMBERS, PERFECT SQUARES, CUBE ... which are easy to identify.
Step 2: Calculate the differences between the numbers. Observe the pattern in the
differences. If the differences are growing rapidly it might be a square series, cube
series, or multiplicative series. If the numbers are growing slowly it is an addition or
subtraction series.
If the differences are not having any pattern then
1. It might be a double or triple series. Here every alternate number or every 3rd
number form a series
2. It might be a sum or average series. Here sum of two consecutive numbers gives 3rd
number. or average of first two numbers give next number
Step 3: Sometimes number will be multiplied and will be added another number So we
need to check those patterns
TYPES :
I. Prime number Series :
Example (1) : 2,3,5,7,11,13, ...........
Answer : The given series is prime number series . The next prime number is 17.
Example (2) :2,5,11,17,23,...........41.
Answer: The prime numbers are written alternately.
II. Difference Series :
Example (1): 2,5,8,11,14,17,...........,23.
Answer: The difference between the numbers is 3. (17+3 = 20)
Example (2): 45,38,31,24,17,...........,3.
Answer: The difference between the numbers is 7. (17-7=10).
III. Multiplication Series:
Generally, two kinds of series are asked in the examination. One is based on numbers
and the other based on alphabets.
Step 1: Observe if there are any familiar numbers in the given series. Familiar numbers
are PRIME NUMBERS, PERFECT SQUARES, CUBE ... which are easy to identify.
Step 2: Calculate the differences between the numbers. Observe the pattern in the
differences. If the differences are growing rapidly it might be a square series, cube
series, or multiplicative series. If the numbers are growing slowly it is an addition or
subtraction series.
If the differences are not having any pattern then
1. It might be a double or triple series. Here every alternate number or every 3rd
number form a series
2. It might be a sum or average series. Here sum of two consecutive numbers gives 3rd
number. or average of first two numbers give next number
Step 3: Sometimes number will be multiplied and will be added another number So we
need to check those patterns
TYPES :
I. Prime number Series :
Example (1) : 2,3,5,7,11,13, ...........
Answer : The given series is prime number series . The next prime number is 17.
Example (2) :2,5,11,17,23,...........41.
Answer: The prime numbers are written alternately.
II. Difference Series :
Example (1): 2,5,8,11,14,17,...........,23.
Answer: The difference between the numbers is 3. (17+3 = 20)
Example (2): 45,38,31,24,17,...........,3.
Answer: The difference between the numbers is 7. (17-7=10).
III. Multiplication Series:
