Know the alphabet positions
Coding questions are fast once you know positions without counting.
Letter | A | E | J | O | T | Y |
|---|---|---|---|---|---|---|
Position | 1 | 5 | 10 | 15 | 20 | 25 |
Opposite letters add up to 27: A–Z, B–Y, C–X, D–W, E–V, F–U, G–T, H–S, I–R, J–Q, K–P, L–O, M–N.
Common patterns
Pattern | Example |
|---|---|
shift forward by n | CAT → DBU (+1) |
shift backward by n | GOLD → EMJB (−2) |
reverse the word | TABLE → ELBAT |
opposite letters | CAT → XZG |
letter positions | CAB → 3 1 2 |
sum of positions | PEN → 16 + 5 + 14 = 35 |
reverse positions (A = 26) | DOG → 23 + 12 + 20 = 55 |
Decoding method
Write the original word and its code one under the other.
Compare letter by letter: is the shift constant? Is the order reversed? Do the pairs add up to 27?
Apply exactly the same rule to the new word.
Sentence codes
Words are coded as whole tokens. Compare sentences that share words: the shared word must have the shared code.
Example.
"sky is blue" = "ta na pa"
"blue sea" = "pa ko"
"sea is deep" = "ko na lu"
"blue" is in the first two sentences and "pa" is the only common code, so blue = pa. Similarly is = na and sea = ko. That leaves sky = ta and deep = lu.
Shortcuts and tricks
The standard way is to write out letter positions and compare. Two facts make most letter codes quick.
EJOTY for positions
Example: the position of R.
Standard way: count A, B, C, … up to R: 18.
Shortcut: remember E = 5, J = 10, O = 15, T = 20, Y = 25. R is 3 after O: 18.
Opposite letters add to 27
Example: the opposite of H.
Standard way: pair up the alphabet from both ends (A–Z, B–Y, …) until you reach H.
Shortcut: H = 8, so its opposite is at 27 − 8 = 19, which is S.
Reverse positions
Example: the reverse-alphabet value of K (A = 26, Z = 1).
Standard way: count backwards from Z: Z = 1, Y = 2, … K = 16.
Shortcut: reverse value = 27 − position = 27 − 11 = 16.
Sentence codes: compare pairs
Find two sentences that share one word; the code they share is that word. Repeat with another pair until the word asked for is the only one left.
Exam tips
Check the first and last letters first; most patterns show up there.
A word and its code having the same letters in a different order is a rearrangement code.
Position codes are often "+1" or "opposite" in disguise.