How to crack code and cipher questions
Cracking substitution codes
Compare the example word with its coded form letter by letter, name the rule exactly, and apply it mechanically.
Updated
'APPLE is written BQQMF' — one comparison tells you everything: A→B, P→Q, L→M, E→F. Every letter moved +1. Coding items are tests of care: find the rule from the example, verify it on every letter, apply without improvising.
The rule inventory
The workhorses: shifts (every letter moves ±k places, wrapping at the ends), reversal (the word written backwards), and position codes (letters replaced by their alphabet numbers, A=1). Beyond those, harder items use a mirror alphabet (A↔Z, B↔Y — a flipped alphabet, not a shift), stacked rules (reversed AND shifted), an alternating shift (the 1st, 3rd, 5th… letters move one way — and on the hardest items the letters between them move the opposite way), and full keyword substitution rows where each letter is replaced by the letter standing at its position in a scrambled row. Check shift first — it's most common — by comparing first letters.
The question can flip too
Not every item says 'code this new word'. Some hand you the code and ask you to DECODE it — run your rule backwards. Some ask for the rule itself ('how many places did every letter move?'). And some show five coded pairs, four obeying one code, and ask which one BREAKS it — verify the rule on the others, then hunt for the traitor. Same rules, different directions; read the question before you fix your direction of travel.
Verify on every letter
A rule confirmed on one letter is a hypothesis; on all letters, a fact. Repeated letters are the free gift: APPLE's double P must map to a double letter — any candidate rule that breaks the doubling is dead.
The strategy
- Line up example and code vertically, letter over letter.
- Compute the first letter's shift; test it on the rest.
- No single consistent shift? Check reversal, position numbers, the mirror alphabet (A↔Z), a shift on alternating letters (same or opposite directions), then reverse-plus-shift.
- Apply the verified rule to the target word slowly — the traps are your own hurried slips.
Common traps
- Wrong direction (+2 read as −2): the options include the backwards application — and decoding questions require the backwards direction on purpose.
- Off-by-one shifts and forgotten wraps (Y+3 = B).
- In position codes: 0-based or off-by-one numberings appear among the options.
- In stacked codes: applying only one of the two steps, or shifting in the wrong direction.
Speed · ~40s/item: 30–60 seconds. Most of it belongs on verification — application should be mechanical.
Try it yourself: 4 practice questions
Pick an answer, then reveal it. Nothing is recorded, there is no clock, and none of these questions is ever used in a test.
In a certain code, WINDOW is written as BNSITB, and every letter has moved the same number of places forward through the alphabet (past Z it carries on from A). How many places is that?
Reveal the answer
The answer is D — 5.
Show why — the worked reasoning
In a certain code, SUMMER is written as UWOOGT, and every letter has moved the same number of places forward through the alphabet (past Z it carries on from A). How many places is that?
Reveal the answer
The answer is E — 2.
Show why — the worked reasoning
In a certain code, PLANT is written as TNALP. How is TRAIN written in the same code?
Reveal the answer
The answer is E — NIART.
Show why — the worked reasoning
In a certain code, SMILE is written as TNJMF. How is RIVER written in the same code?
Reveal the answer
The answer is D — SJWFS.
Show why — the worked reasoning
Try questions like this
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Questions people ask
Will codes and ciphers questions be on the free test?
Maybe. The free test gives verbal & logic 5 of its 20 questions, spread across 11 different question types, so any one test may or may not include this kind.