Codebreaker HQ
Spy agency: crack intercepts and decrypt the secret message
- Letter Codes
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Steam from Appledore (A) to Zed Terminus (Z), with a station for every letter. Each right answer turns the signal green and the train surges on, and three in a row goes Express: golden carriages and double miles until a red signal.
Included in every Prep4All plan. Codebreaker HQ is free to try first.

Alphabet Express practises the letter work in 11+ verbal reasoning. A journey is 16 signals in four legs, A to F, G to M, N to S and T to Z, and every journey meets all six topics: alphabet position, letter from a clue, alphabetical order, letter identification, missing letters and letter sequences. The fourth signal of each leg is a junction, a harder question that takes the train over the viaduct when it is right.
A wrong answer is a red signal: the train brakes, the trap is explained and it runs on with care, so every journey still reaches Zed Terminus. Quick answers run at full steam for extra miles, and signals get harder after a streak and easier after a red. The journey log explains every trap. Reach Express Champion to unlock the Night Sleeper, a moonlit route that runs until dawn.
Letter series and missing letters are two of GL Assessment’s 21 verbal reasoning question types, and many of the others rely on knowing the alphabet forwards and backwards, with each letter’s position from A = 1 to Z = 26.
Questions from the game, for you to try together. Have a go before opening the answer.
What is the 9th letter after C in the alphabet?
L — C = 3, and 3 + 9 = 12, which is L.
A dictionary page has the guide words NIGHT and NOSE. Which of these words would be on that page? NIGHT / NOSE
NOISE — NOISE comes after NIGHT and before NOSE. NIGHT comes before NOISE: at the 2nd letter, I comes before O; NOISE comes before NOSE: at the 3rd letter, I comes before S.
Which letter is in WATCH but not in TEACHER? WATCH / TEACHER
W — WATCH: W, A, T, C and H. Cross out A, T, C and H, which are in TEACHER. Only W is left.
Spy agency: crack intercepts and decrypt the secret message
Detective agency: three cases, an evidence board and the final deduction
Island voyage: five channels, changing weather and the Storm Channel
Every game, every level and the daily challenge are included in every Prep4All plan, with lessons, practice tests and mock exams. Every plan starts with a 7-day free trial.