Mirror & Water Images
🔒 Log in to trackMirror images (vertical mirror)
🔒 Log in to trackA mirror placed vertically (to the left or right of the object — the result is the same) swaps left and right but keeps top and bottom. For a word or number this does two things at once:
- the order of characters is reversed (the last character appears first), and
- each character is flipped left-to-right (R faces the other way, 4 turns round).
Letters with a vertical axis of symmetry — A H I M O T U V W X Y — look unchanged when flipped, so they are the fastest check points; asymmetric ones like B C D E F G J K L N P Q R S Z and digits 2 3 4 5 6 7 9 decide between options.
Detailed notes
What a vertical mirror does
Stand in front of a mirror and raise your right hand: the image raises the hand on the other side. A vertical mirror swaps left and right and keeps top and bottom. Whether the mirror is on the left or the right of the object, the image looks the same; only its position changes.
For a word, number or code this does two things together:
- The order is reversed: the last character comes first.
- Each character is flipped left-right: R, E, S, N, 2, 4, 7 face the other way.
Top stays top. A letter is never upside down in a mirror image.
Symmetric letters and digits
Capital letters with a vertical line of symmetry look the same in a mirror: A H I M O T U V W X Y (and the digits 0 and 8).
Every other capital looks reversed: B C D E F G J K L N P Q R S Z.
- A word looks exactly the same in a mirror only if it reads the same backwards and every letter is in the list above. Examples: MOM, WOW, TOOT, MAAM.
- A letter looks the same letter by letter only if it is in the list. For single-letter counting, order does not matter.
Four-step check for option questions
- First character of the image = last character of the word. Reject options that start with the wrong character.
- Check one asymmetric character (R, E, S, 4, 7...). It must face the other way.
- Make sure top stays top. If a letter is upside down, that option is a water image or a 180° turn.
- Check the middle characters only if two options are still left.
The usual wrong options
- Water image: order kept, letters upside down. (Wrong axis.)
- 180° turn: order reversed and letters upside down. This is a mirror image plus a water image.
- Reversed only: order reversed, but letters not flipped.
- Flipped only: letters flipped, but order kept.
Figures
For a line figure, every point moves to the same distance on the other side of the mirror line. Things on the left go to the right; heights do not change. Pick one clear feature (a dot, a shaded corner, a short tail) and check where it lands.
- A feature in the top-left corner goes to the top-right in a mirror image.
- If it went to the bottom-left, that is a water image; bottom-right is a 180° turn.
Worked example
Mirror image of REASON. The image reads N O S A E R from left to right. A and O are symmetric and look the same. N, S, E and R face the other way. An option showing N O S A E R with upside-down letters is a 180° turn, not a mirror image.
Quick revision
- Mirror: order reversed + each character flipped left-right; top stays top.
- Symmetric capitals: A H I M O T U V W X Y; digits 0 and 8.
- Same word in a mirror = palindrome made only of symmetric letters.
- Figures: left ↔ right, height unchanged; track one corner feature.
- Upside-down option = water image or 180° turn, never a mirror image.
Types of questions asked
Every way this subtopic shows up in exams — how to recognise it, the formula or logic to use, and a solved example.
Type 1: Mirror image of a wordvery common3 practice Q
A word in capitals with four image options; mirror placed vertically on one side.
- The image starts with the last letter.
- Every letter is flipped left-right; symmetric letters look unchanged.
- Nothing is upside down.
Why: a vertical mirror only swaps left and right.
Example: Which describes the mirror image of REASON?
Letters in the order N O S A E R, with N, S, E, R facing the other way and A, O unchanged.
Type 2: Mirror image of a number or codecommon3 practice Q
A number, or a mix of letters and digits, with image options.
- Reverse the order.
- Flip each character left-right; 0 and 8 stay the same.
- Digits like 2, 3, 4, 5, 7 face the other way.
Why: digits follow the same rule as letters.
Example: What is the order of characters in the mirror image of 4R95J?
Reversed: J 5 9 R 4, each flipped left-right.
Type 3: Mirror image of a figurevery common3 practice Q
A line figure with a vertical mirror line (often marked M) beside it.
- Pick a clear feature: dot, shaded part or tail.
- Move it to the other side at the same height.
- Reject options where it moved up or down.
Why: a vertical mirror keeps heights and swaps sides.
Example: A figure has a dot in its top-left corner. Where is the dot in its mirror image?
Top-right corner. Bottom-left would be the water image, bottom-right a 180° turn.
Type 4: Letters that look the same in a mirrorcommon2 practice Q
How many letters of a word, or which letters, look unchanged in a mirror.
- Tick letters from A H I M O T U V W X Y.
- Count the ticks (repeated letters count each time).
Why: only these capitals have a vertical line of symmetry.
Example: How many letters of MATHEMATICS look the same in a mirror?
M, A, T, H, M, A, T, I = 8. E, C and S look reversed.
Type 5: Word that looks the same in a mirroroccasional2 practice Q
Which word (or number) will look exactly the same in a vertical mirror.
- The word must read the same backwards.
- Every letter must be symmetric (A H I M O T U V W X Y).
Why: the mirror reverses order and flips each letter, so both must be undone.
Example: Which looks the same in a mirror: NOON, TOOT or DEED?
TOOT. NOON and DEED are palindromes, but N, D and E are not symmetric.
Shortcut tricks
⚡ Check the end characters first
In a vertical-mirror image the last character of the original stands first, flipped. Eliminate options by looking only at the first and last characters.
Example: Q. Mirror image of PEN7?
Sol. The image starts with a flipped 7 and ends with a flipped P. Any option starting with a normal P (order not reversed) or a normal 7 (not flipped) is wrong.
Reversed order + flipped characters — test both on one end.
⚡ Symmetric-letter shortcut
A word made only of A H I M O T U V W X Y that reads the same backwards (a palindrome, e.g. TOOT, WOW) looks identical in a vertical mirror.
Example: Q. Does MOM look the same in a vertical mirror?
Sol. M, O are symmetric and MOM is a palindrome → yes.
Symmetric letters + palindrome → unchanged.
Where students lose marks
Flipping each letter but keeping the original order.
Reversing the order but not flipping the asymmetric letters.
Confusing the mirror image with the water image (top-bottom flip).
Practice sets — 18 questions
Sets of 10, mixed across the question types above. Each answer comes with a step-by-step explanation.
Topic test · 10 questions
Suggested time 7 min · wrong answers go to your mistake notebook automatically.