Coding and decoding questions are asked in many competitive exams but the level of questions differs. For example in SSC, the level of questions in easy to medium while in IBPS exams, the level of questions is difficult. In IBPS, coding and decoding questions comes under Machine Coding and Decoding Topic.

But in SSC exams, Coding Decoding questions asked are quite easy as compared to IBSP exams. We have already given shortcut tricks to Machine Coding and decoding questions for IBPS exams. 

For solving coding decoding questions, you have to learn a few basics.

1. Letter position (A=1, B=2, C=3, D=4…….Y=25, Z=26)
2. Opposite position of letters (A=26, B=25….Z=1)
3. Opposite of each letter (A is opposite to Z and B is opposite to Y and C is opposite to X…..learn all alphabets opposite)

Here are coding and decoding questions shortcut tricks (easy solution).
Type-1- Letter : In a certain code, CODING is written as DPEJOH. How will DECODING be written in that code?
Answer: the simple formula or the shortcut trick to solve this type of question is to compare the first coded words. The number of steps that are increase of each letter in first conversion, the same formula should be applied to code that has to be converted. Just like in CODING and DPEJOH, 1 point step is added (C+1=D, O+1=P as per alphabet).
Now compare each letter one to another like compare each letter of CODING and DPEJOH.
Comparing 1st letter of CODING to 1st of DPEJOH.
C is converted to D.
You know C’s next letter in alphabets is D.
O’s next letter is P.
D’s next letter is E.
I’s next letter is J.
N’s next- O
G’s next- H
This was how CODING was converted to DPEJOH. Now the same way you have to convert DECODING.
D- is converted to -E.
So DECODING should be converted to EFDPEJOH.
Note: in the shown conversion of a question, there might be letters in which +2, +3, +4 etc. positions are added. In that case, add the same position to the asked word.
Type 2-Number: Position of letter are added or remains constant.
The Main idea to solve these questions is to apply the conversion that is shown like in above question “CODING is written as DPEJOH”. You have to apply the same conversion to DECODING word. Same trick you have to apply to Number coding. For converting letters to numbers, you have to remember the conversion basic given above.
Like FEAR can be converted to 65118 as shown below

Or it can also be converted to the addition of these means 6+5+1+18=30. The same way should be applied for the asked CODE.
Learn Coding & Decoding Part 1