Coding-Decoding

Letter-shifting, substitution, and number coding — find the hidden rule and apply it to a new word.

📖 ~4 min read 🧠 RRB NTPC / Group D — Reasoning

Type	How It Works
Letter shifting	Each letter shifted forward/backward by a fixed number of positions
Substitution coding	A direct letter-word or number-word key applied to a new sentence
Number coding	Letters converted to alphabet position numbers (A=1…Z=26)

💡 Example: CAT is coded as DBU (each letter +1). Then DOG is coded as EPH.

💡 Write out the alphabet with position numbers 1-26 as a quick reference strip — turns "shift by 3" into simple addition/subtraction.

This free chapter covers the key concepts. For complete coverage with 500+ MCQs, mock tests, and previous year analysis — grab the premium eBook.