Coding-Decoding

Coding decoding is a part of the arithmetic reasoning and aptitude test for competitive exams. The main challenge behind coding-decoding questions is to understand the principle of the logic working for making the codes. The tips and tricks discussed here will help in understanding the logic.

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Coding decoding tricks

The location of 26 alphabets and their reverse order should be remembered for solving coding questions. It could be remembered easily by remembering EJOTY, where E is 5, J is 10, O is 15, T is 20 and Y is 25. In the reverse order, Y is 2, T is 7, O is 12, J is 17 and E is 22. Other alphabets could be remembered from them. Also, the reverse position of the alphabets could be found by subtracting its sequence number from 27.

There are a few types of coding-decoding common in the competitive examinations

The coding-decoding examples with the same number of addition

In this type of coding, a similar number is added to the sequence number of the alphabets to code a word. For example, If NUT is coded as OVU, find out the code for COP.

Here, the code of NUT is N + 1 = O , U + 1 = V , T + 1 = U. So the code of COP will be C + 1 = D, O + 1 = P, P + 1 = Q, the code is DPQ

The coding-decoding examples with the same number of subtraction

In this type of coding, a similar number is subtracted from the sequence number of the alphabets to code a word. For example, If NUT is coded as MTS, find out the code for COP.

Here, the code of NUT is N — 1 = M , U — 1 = T , T — 1 = S. So the code of COP will be C — 1 = B, O — 1 = N, P — 1 = O, the code is BNO

The coding-decoding examples with the added number of subtraction

In this type of coding, one or several numbers are added before subtracting from the sequence number of the alphabets to code a word. For example, If NUT is coded as MSQ, find out the code for COP.

Here, the code of NUT is N — 1 = M , U — 2 = S , T — 3 = Q. So the code of COP will be C — 1 = B, O — 2 = M, P — 3 = M, the code is BMM

The coding-decoding examples with the added number of addition

In this type of coding, one or several numbers are added before adding to the sequence number of the alphabets to code a word. For example, If NUT is coded as OWW, find out the code for COP.

Here, the code of NUT is N + 1 = O , U + 2 = W , T + 3 = W. So the code of COP will be C + 1 = D, O + 2 = Q, P + 3 = S, the code is DQS

The coding-decoding examples with reverse or jumbled order

In this type of coding, the alphabets are reversed or jumbled to code a word. For example, If NUT is coded as TUN, find out the code for COP.

Here, the code of NUT is the reverse of the alphabets, So the code of COP will be POC.

The coding-decoding examples with reverse order and then addition or subtraction

In this type of coding, the alphabets are reversed or jumbled and then numbers are added or subtracted to make the sequence number of the codes. For example, if NUT is coded as SUO, find out the code for COP. 

Here the code of NUT is found by reversing the order of the alphabets, then 1 is subtracted from T, O has been kept intact and 1 is added to N. So the code of COP will be found by first reversing it into POC, then P – 1 = N, C + 1 = D, the code is NOD. 

Conclusion

Mathematical reasoning and logical reasoning are also needed to understand coding-decoding better. The competitive exams only follow a few logics for the coding-decoding questions. The basic formulas will help in solving them.