Understanding Coding-Decoding

Coding questions are very popular with most examiners. There is so much of variety in these questions, that one know 30 – 40 types of coding in order to attempt these questions in the examination.While framing coding questions, the examiner tries to include one or two very new types of coding in the examination. In order to gain proficiency in this topic, besides reading and understanding all the questions, try to frame 20 –30 questions on this theme and ask one of your friends to do the same. Then first attempt the questions made by your friend and simultaneously, let him solve the questions made by you. Then by sitting together discuss all the questions. This is a very useful technique to gain mastery on this topic.  

In such a question, generally, a word and its code are given and the students are asked to find the code for the other given word, applying the same logic, as what has been applied in the given examples.

But before we proceed to discuss the various types of questions related to coding,it is better to have an idea regarding the general types of coding. Some of the major types of coding are:

1.   Constant addition in the position of alphabets.
2.   Constant subtraction in the position of alphabets.
3.   Denoting the position of alphabets in the whole alphabetical order.
4.   Addition of the positions of all the alphabets to make code for the word.
5.   Constant addition and subtraction respectively in the position of all the    alphabets.
6.   Squaring the number of letters in the word.
7.   Arranging the letters in the alphabetic order.
8.   Arranging the letters given in the main word, in the reverse order.
9.   Interchanging each pair of the letters, in the whole word.
10.  Constant addition and then reversing the letters to make the final code.

Now we will discuss all these types of coding and much more with the help of examples.


You must have noticed from the above points, that it is very important for the student to know the order of all the alphabets.

The following method can be applied to learn the alphabetic order.

I.THE ALPHABET: The normal English alphabet contains 26 letters in all, as shown above

(Usually,questions on alphabet are accompanied by this normal alphabet). From A to M,the alphabet completes its first half, while the other half starts from N and ends at Z.

A-M - 1-13  (First Alphabetical Half )
N-Z –14-26 (Second Alphabetical Half)

II.EJOTY: For purpose of convenience, it is helpful to remember this simple formula called EJOTY, with the help of which you can easily find the position of any letter without much effort. But for practical purposes, you should learn by heart the positions of different letters in the alphabet, where these five letters represent the following positions.

E    J     O      T      Y
5    10    15    20    25