This is one of the easy topics but it requires a quick understanding of the terms like, right, left, in the middle of and so on. Also, quick calculations (addition, subtraction, multiplication, etc.) are required to solve numerical series. You can easily score 2-3 marks in this topic by answering these questions attentively.

The series can be of following topics:

• Numerical Series
• Alphabet Series
• Alphanumeric Series
• Alphanumeric Symbol Sequence series

Let’s discuss each of them in detail with some suitable examples:

1. Numerical Series: It consists of some set of numbers and you have to perform the operations on it as per the requirement of the question.

Eg: 723       316      451      539      876

Examples of question format:

Q1. If in each number, the first and the last digits are interchanged, then how many numbers are odd

1. 0 
2. 1 
3. 2 
4. 3 
5. 4 

Ans. d

Q2. If in each number, all the three digits are arranged in ascending order, which of the following will be the biggest number in the new arrangement?

1. 669 
2. 352 
3. 339
4. 575 
5. None of these

Ans. A

Q3. If each number is multiplied by 3, then what is the sum of the first digits of the largest and the second largest number?

1. Zero
2. 3 
3. 1
4. 4
5. None of these 

Ans. D

After multiplying each number by 3, we get new numbers as 1056, 1725, 2007, 1017, and 2649. So, the required sum is 2+2=4

So, these were some examples of Numerical Series. Now let's move to next series. 

2. Alphabet Series: It consists of a set of words where you have to apply the operations.

Eg: CUT    RAT    LIN    HUT    LAN

Examples of question format:

Q1. If the third alphabet in each of the word is changed to the next alphabet in English alphabetical order, how many words thus formed have more than two different consonants?

1. None 
2. One 
3. Two 
4. Three 
5. Four 

Ans. D. 

After arranging, the words are GHC    LAT     MKU     BGP    SRW 
GHC, BGP, and SRW have more than two different consonants.

Q2. If in each of the words, all the alphabets are arranged in reverse English alphabetical order within the word, how many words will end with a vowel?

1. None 
2. One 
3. Two 
4. Three 
5. Four 

Ans. B

After arranging, the words are HGB SLA TMK OGB VSR 
Only SLA ends with the vowel.

Q3. How many letters are there in the English alphabetical series between the second letter of the last word from the left and third letter of the fourth word from the right?

1. None 
2. One 
3. Two 
4. Three 
5. Four

Ans. A. 

The second letter of the last word from the left is ‘R’. 
The third letter of the fourth word from the right is ‘S’. 
So between R and S, there is no letter in English alphabetical series.

Q4.If the given words are arranged in the order as they would appear in the English dictionary from right to left, which of the following will be third from the right?

1. GHB 
2. LAS 
3. MKT 
4. BGO
5. SRV 

Ans. B. 

After arranging, the SRV MKT LAS GHB BGO, LAS is third from right

Q5.If in each of the given words, each of the consonants is changed to the next letter and each vowel is left unchanged, in how many words thus formed will there be no vowel?

1. None
2. One 
3. Two 
4. Three 
5. Four 

Ans. B. 

After arranging, the words are HIC MAT NLU CHO TSW. 
In TSW, there is no vowel.

Now, we will discuss another type of series. 

3. Alphanumeric Series: This series will be consisting of alphabets and numbers only.

Eg: F 6 H 8 W I 9 Y 4 K 3 L 3 T J E 9 1 0 M 1

Examples of question format:

Q1. How many such consonants are there in a sequence which are both immediately preceded by and immediately followed by a number?

1. 1
2. 2
3. 3
4. 4
5. 5

Ans: d

Letters H, Kand amd M are immediately preceded by or immediately followed by a number.

Q2. After dropping all the numbers, which letter will be second to the left of the fifth letter from the right end?

1. F
2. H
3. Y
4. W
5. T

Ans: c

After dropping all the numbers, second to the left of the fifth letter from the right end or 7th from the right end is Letter Y.

Now, we will discuss next type of series:

4. Alphanumeric Symbol Sequence series: It will contain alphabets, numbers, and symbols arranged in a sequence and you have to answer questions based on that.

Eg: 5 P ) S Y 9 6 # 1 D ? 1 ^ Q % d T % Q ! c 4

Examples of question format:

Directions: Study the following digit-letter-symbol sequence carefully and answer the questions. 

A ? I 4 > 7 C 6 = U K 8 3 # O 5 Z 1 & E 2 < *

Q1.How many symbols are preceded by a digit and succeeded by a vowel?

1. 0 
2. 1 
3. 2 
4. 3 
5. More than 3 

Ans. d

A ? I 4 > 7 C 6 = U K 8 3 # O 5 Z 1 & E 2 < * , Symbols =, # and & are preceded by a digit and succeeded by a vowel. 

Q2. If all the vowels are replaced with their succeeding letters and all the consonants are replaced with their preceding letters. How many letters appear more than once?

1. 0 
2. 1 
3. 2 
4. 3 
5. More than 3 

Ans. C

The original sequence is A ? I 4 > 7 C 6 = U K 8 3 # O 5 Z 1 & E 2 < * 
The new sequence after replacement is B ? J 4 > 7 B 6 = V J 8 3 # P 5 Y 1 & F 2 < * 
So, B and J appear twice. 

Q3.If the first 10 elements are interchanged with the last 10 elements and the order of all of them is reversed then which element will be the 9th element from the left?

1. = 
2. 6 
3. # 
4. O 
5. 5 

Ans. D

The original sequence is A ? I 4 > 7 C 6 = U K 8 3 # O 5 Z 1 & E 2 < * 
The new sequence is * < 2 E & 1 Z 5 O # K 8 3 U = 6 C 7 > 4 I ? A 
O is 9th from the left. 

Q4. If the digits that come after a vowel are increased by 1 and the digits that come after a consonant are decreased by 1. What will be the total sum of the changed digits?

1. 24 
2. 25 
3. 26 
4. 27 
5. 28 

Ans. C

A ? I 4 > 7 C 6 = U K 8 3 # O 5 Z 1 & E 2 < * 
Digits after vowel are 4, 5 and 2. So, new digits are 5, 6 and 3 
Digits after consonant are 6, 8 and 1. So, new digits are 5, 7 and 0 
Total Sum = 5+6+3+5+7+0 = 26 

• Fasten your calculation so that you can easily solve the series.
• Learn the ranks of alphabets to quickly apply the operations on it.
• Be clear with the use of operations; “to the right/left of”, “in the middle of”, “to the right or left of” and vice versa.
• Practice lot of questions to master the topic