Mirror & Water Images
🔒 Log in to trackMirror images (vertical mirror)
🔒 Log in to trackA vertical mirror swaps left and right and keeps top and bottom. In a word or number, the order of the characters is reversed, and every character is flipped left to right. Letters with a vertical line of symmetry look unchanged. Use them as quick check points.
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. Top stays top. It does not matter if the mirror is on the left or the right of the object. The image looks the same.
For a word, number or code, two things happen together:
- The order is reversed. The last character comes first.
- Each character is flipped left to right. R, E, S, N, 2, 4 and 7 face the other way.
Rule: Mirror image = reverse the order + flip every character. Top stays top.
Letters that look the same
Capitals 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.
All other capitals look reversed: B C D E F G J K L N P Q R S Z.
A whole word looks the same in a mirror only if two things are true:
- it reads the same backwards, and
- every letter is in the list above.
Examples: MOM, WOW, TOOT, MAAM.
Four-step check for options
- The first character of the image is the last character of the word. Reject options that start with anything else.
- Check one asymmetric character, such as R, E, S, 4 or 7. It must face the other way.
- Check that top stays top. An upside-down letter means a water image or a half turn.
- Check the middle characters only if two options are left.
Tip: Two checks, the first character and one flipped letter, often leave only one option.
The usual wrong options
- Water image: order kept, letters upside down.
- Half turn: order reversed and letters upside down. It is a mirror image plus a water image.
- Reversed only: order reversed, but letters not flipped.
- Flipped only: letters flipped, but order kept.
Figures
In a line figure, every point moves to the same distance on the other side of the mirror line. Left goes to right. Height does not change.
Pick one clear feature: a dot, a shaded corner or a short tail. Check where it lands.
- Top-left goes to top-right in a mirror image.
- Bottom-left would be a water image.
- Bottom-right would be a half turn.
Place in the image
Some questions ask which letter is at a given place, counting from the left, in the mirror image.
Write the word backwards. Then count from the left in the new order.
Example: the mirror image of PLANET reads T, E, N, A, L, P. The 3rd letter from the left is N.
Note: A mirror on the left or on the right gives the same image. Only its position changes.
Worked example
Mirror image of REASON.
The image reads N O S A E R from left to right. A and O are symmetric, so they 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 half turn, not a mirror image.
Question types you will see
Each type: how to recognise it, the method step by step, and one question to try.
Mirror image of a word
A word in capitals with four image options. The mirror is placed vertically beside it.
Write the letters in reverse order.
Flip every letter left to right. A, H, I, M, O, T, U, V, W, X, Y look unchanged.
Check that nothing is upside down.
A vertical mirror only swaps left and right.
Which describes the mirror image of REASON?
Show solutionHide solution
Reverse the order: N, O, S, A, E, R.
A and O are symmetric, so they look the same.
N, S, E and R face the other way.
N O S A E R, with N, S, E and R facing the other way and A, O unchanged
Mirror image of a number or code
A number, or letters and digits mixed, with image options.
Reverse the order.
Flip each character left to right. 0 and 8 stay the same.
2, 3, 4, 5, 7 and 9 face the other way.
Digits follow the same rule as letters.
What is the order of characters in the mirror image of 4R95J?
Show solutionHide solution
Reverse the order: J, 5, 9, R, 4.
None of these is symmetric, so all five face the other way.
J 5 9 R 4, each flipped left to right
Mirror image of a figure
A line figure with a vertical mirror line, often marked M, beside it.
Pick a clear feature: a dot, a shaded part or a tail.
Move it to the other side of the mirror line, at the same height.
Reject options where it moved up or down.
A vertical mirror keeps heights and swaps sides.
A figure has a dot in its top-left corner. Where is the dot in its mirror image?
Show solutionHide solution
Left and right swap, height stays the same.
Bottom-left would be a water image. Bottom-right would be a half turn.
Top-right corner
Letters that look the same in a mirror
How many letters of a word, or which letters, look unchanged in a mirror.
Tick the letters from A H I M O T U V W X Y.
Count the ticks. A repeated letter counts each time.
Only these capitals have a vertical line of symmetry.
How many letters of MATHEMATICS look the same in a mirror?
Show solutionHide solution
M, A, T, H, M, A, T, I are symmetric.
E, C and S are not.
8
Word that looks the same in a mirror
Which word or number looks exactly the same in a vertical mirror.
Check that the word reads the same backwards.
Check that every letter is symmetric.
The mirror reverses the order and flips each letter. Both must change nothing.
Which looks the same in a mirror: NOON, TOOT or DEED?
Show solutionHide solution
All three read the same backwards.
TOOT uses only T and O, which are symmetric.
N, D and E are not symmetric.
TOOT
Position of a letter in the image
The question asks which letter is at a given place, counting from the left, in the mirror image.
Write the word backwards.
Count from the left in the new order.
The mirror reverses the order, so the places reverse too.
Which letter is 3rd from the left in the mirror image of PLANET?
Show solutionHide solution
Reverse the word: T, E, N, A, L, P.
T is 1st, E is 2nd, N is 3rd.
N
Shortcuts that save time
The image starts with the last character of the word, flipped. Reject options by looking at the first character only.
What does the mirror image of PEN7 start with?
Show solutionHide solution
The last character is 7.
It comes first in the image and faces the other way.
A flipped 7
A word made only of A H I M O T U V W X Y that reads the same backwards looks unchanged in a vertical mirror.
Does MOM look the same in a vertical mirror?
Show solutionHide solution
M and O are symmetric.
MOM reads the same backwards.
Yes
Mistakes to avoid
Where most students lose marks on this subtopic.
Flipping each letter but keeping the original order.
Reverse the order first. The last character comes first.
Reversing the order but not flipping the letters.
Flip every asymmetric letter left to right as well.
Turning letters upside down in a mirror image.
A vertical mirror keeps top and bottom. Upside down is a water image.
Saying a palindrome always looks the same in a mirror.
Every letter must also be symmetric. NOON reads the same backwards, but N is not symmetric.
Using the mirror list of letters for a water image.
Water has its own list: B C D E H I K O X.
Quick revision
Read this the night before the exam.
Mirror image: reverse the order and flip every character left to right.
Top stays top. Upside down is never a mirror image.
Symmetric capitals: A H I M O T U V W X Y. Symmetric digits: 0 and 8.
Same word in a mirror: a palindrome made only of symmetric letters.
Figures: left and right swap. Height does not change.
First character of the image = last character of the word.
Practice: 18 questions
Sets of 10, mixed across the question types above. Every answer has a step-by-step explanation.
Topic test · 10 questions
Suggested time 7 min · wrong answers go to your mistake notebook automatically.