Code questions are solved by writing the alphabet out and working one letter at a time, checking the shift for every single letter rather than assuming it stays the same. That assumption is where most marks are lost.
It helps to split verbal reasoning the way you would split mathematics, into applied topics and language topics. The applied ones have a rule. Teach the rule, practise it, and a child improves quickly. The language ones, anagrams and antonyms and the rest, rest on reading and cannot be taught around.
This is an applied type, which is good news: it is one of the fastest places to pick up marks.
Constant shift codes
The simplest form moves every letter by the same amount.
If CAT is written as DBU, what is DOG?
C to D is one step forward. A to B is one step. T to U is one step. The rule is plus one, so DOG becomes EPH.
Changing shift codes, where it gets interesting
Here is the type that catches children who assume the shift is constant.
If LAMP is written as MCPT, what is the rule?
| Letter | Becomes | Shift |
|---|---|---|
| L | M | +1 |
| A | C | +2 |
| M | P | +3 |
| P | T | +4 |
The shift grows by one each time. A child who checks only the first letter concludes the rule is plus one and gets the whole question wrong.
Always check every letter. It costs five seconds and it is the single highest-value habit in this question type.
Number codes
Number codes work the same way with digits standing in for letters.
If CAB is 3 1 2, then each letter is simply its position in the alphabet, so BAD is 2 1 4.
Harder versions apply an operation to the position: double it, add five, or alternate between two rules. The method does not change. Write the positions first, then look for what was done to them.
Matching a code to a word
A common variant gives you several words and several codes, shuffled, and asks which goes with which.
Do not try to crack the rule first. Instead:
- Count the letters. A five letter code cannot belong to a four letter word. That alone often eliminates half the options.
- Look for repeated letters. If a word has a double letter, its code will have a repeated symbol in the same position.
- Only then work out the shift, using whichever pair you have already matched.
Where the marks go
- Assuming a constant shift. Check every letter, every time.
- Not wrapping round. Z plus one is A, not a dead end.
- Counting backwards by mistake. Establish direction before you start.
- Not writing the alphabet down. Same as every applied type.
See our guide to letter sequences, which uses the same alphabet-on-the-page method, and the partnership's familiarisation questions for the answer format.
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Check every letter, not just the first
Codes and coded calculations are in the applied family, alongside letter sequences. There is a rule, it can be taught, and children pick it up quickly. That makes them one of the most efficient things you can work on.
The one habit I drill harder than any other here is checking every letter before deciding the rule. A child sees the first letter has moved on by one, assumes the whole word has, and throws away a question they understood perfectly well. It is not a knowledge problem, it is a speed problem, and it is fixed by making the check automatic.
And if a child is still struggling after the rule has been taught properly, look underneath at the vocabulary. Even in the applied types, a child who does not recognise the word being coded is working with one hand tied behind their back.
Mushtaque Ahmed, Founder of GrammarPath and Bright Mentors
Frequently asked questions
How do you solve 11+ letter code questions?
Write the alphabet out, then compare each letter of the original word with the matching letter of the code and note the shift for every letter separately. Once you have the rule, apply it to the new word, remembering that the alphabet wraps from Z back to A.
What if the shift is different for each letter?
That is a common and deliberate trap. In LAMP becoming MCPT the shifts are plus one, plus two, plus three and plus four. A child who checks only the first letter concludes the rule is plus one and loses the whole question, so always check every letter.
How do number codes work in the 11+?
Usually each letter is replaced by its position in the alphabet, so CAB becomes 3 1 2 and BAD becomes 2 1 4. Harder versions apply an operation to the position such as doubling it or adding a constant, so write the positions out first and then look for what was done to them.
How do you match codes to words when they are shuffled?
Do not start by cracking the rule. Count the letters first, since a five letter code cannot belong to a four letter word, then look for repeated letters, because a double letter in the word appears as a repeated symbol in the same position in the code.
Are code questions worth practising for the 11+?
Yes, they are among the best value in the paper. Codes are an applied question type with a teachable rule, so a child who is shown a reliable method improves quickly and banks marks that are much harder to win in the vocabulary-based question types.