Mirror first, then jumps

The rule is in the pair you are given

One pair, then a second pair linked to it. That link is where the rule comes from. Unless the question names the rule in words, there is nothing else to go on.

MP is to RK. M → R is forward 5. P → K is back 5.

Two letters, same size of jump, opposite directions. Which is why the habit matters more than the arithmetic:

Write both jumps down before you touch the target pair. Never work out the first letter's jump and start answering.

Mirror or jump, and how to tell in three seconds

There are two families, and they look alike on the page.

JUMP — each letter moves along the alphabet by its own amount. MIRROR — A pairs with Z, B with Y, C with X. The pair reflects.

Do the mirror check first, on the pair you are given. It takes three seconds and it is the rule most easily missed — because a mirror pair still looks like two letters that have simply moved.

Why does the question name the rule? Because one pair cannot prove a mirror. X to C is also forward 5, wrapping past Z, and I to R is forward 9. Those two jumps fit XI to CR just as well, and they would turn RA into WJ, not IZ.

So a fair mirror question either names the mirror, as this one does, or gives answer choices that only one rule can reach. If the rule is not named and the pair passes the mirror check, work out the mirror answer first and the jump answer second, and see which one is offered.

The diagram below shows the four mirror pairings from this example.

Both directions, at once

A jump can go either way, and the two letters can go opposite ways from each other.

FX is to IU. F → I is forward 3. X → U is back 3.

Nothing says both letters move the same direction, and nothing says they move by the same amount. Check each letter on its own.

Wrapping past Z

The alphabet is a loop, not a line.

Y + 4: Y → Z → A → B → C.

After Z you carry on from A. Going backwards, before A you carry on from Z. Most pupils know this and still stop at Z under time pressure, so say it out loud as you cross.

If a letter is in the last four or the first four of the alphabet, expect to wrap.

Where do pupils lose marks?

Missing the mirror. Read XI to CR as two jumps and RA becomes WJ — a tidy answer, and not the one a mirror question is asking for.

Assuming one direction, or assuming both letters move by the same amount.

Rushing the count. The counting error does not go away with age — it goes underground, because a child counting fast enough stops checking. What remains is off-by-one.

Letting the pattern stop at Z.

Try it yourself

Each of these uses one of two rules: a mirror, or a jump for each letter. Mirror check first. Then write both jumps down, with a small arrow above each letter, before you answer.

1. TY is to WW as LC is to ___
2. Using the mirror alphabet, XI is to CR as RA is to ___
3. VI is to AE as ZW is to ___
4. HA is to LU as LW is to ___
5. DW is to HT as TG is to ___

Show Answers

How much practice does this type need at home?

Short bursts, with the alphabet written out on the page. The single most useful instruction is "show me both jumps before you show me the answer" — because three of the four errors above are caught by that alone.

When an answer is wrong, it is almost always worth asking which of the four it was. Naming the mistake is what stops it recurring.