---
title: "Find the Mistake Level Up #18: 3 Sudoku Levels | Sudoku Flow"
description: "Three Sudoku boards, one wrong number in each: a 4×4, a 6×6, then a full 9×9. Level Up #18: play every level and see each answer."
url: https://sudokuflow.com/puzzles/level-up-18/
language: en
---
[Puzzles](https://sudokuflow.com/puzzles/) / Level Up #18
Level Up
# Level Up #18
Three boards, each with one wrong number, from a small 4×4 to a full 9×9. Play every level here, at your own pace.
[Watch on YouTube](https://youtube.com/shorts/IbOD4ZAq9Dc)
## Level 1 · 4×4
Tap the digit you think is wrong.
Level Up #18 · Level 1 · 4×4:
```text
1 4 | 3 .
. 3* | 4 1
------+------
. 4* | . 3*
3* 2 | . 4*
```
Digits marked * were filled in by a player; the others were printed with the puzzle.
Show the answer
It's the blue 4 in row 3, column 2. Column 2 already has a printed 4 (row 1, column 2). A printed digit can't be wrong, so the blue one is. The right digit for that cell is 1.
## Level 2 · 6×6
Tap the digit you think is wrong.
Level Up #18 · Level 2 · 6×6:
```text
. 4* 1* | 6 3 5*
3* 6 . | 1 2 .
---------+---------
. 2 3* | . 5 6
6 5* 4 | 2 1* 3
---------+---------
. . . | 5 6* .
2* 1* 6* | . 4 2
```
Digits marked * were filled in by a player; the others were printed with the puzzle.
Show the answer
It's the blue 2 in row 6, column 1. Row 6 already has a printed 2 (row 6, column 6). A printed digit can't be wrong, so the blue one is. The right digit for that cell is 5.
## Level 3 · 9×9
Tap the digit you think is wrong.
Level Up #18 · Level 3 · 9×9:
```text
. 2 1 | 3 . 8 | . 9 6*
3 . 8 | . 9* . | . 2 1*
7 9 6* | 2 1* 4 | 3 5* 8
---------+----------+---------
2 5* 4* | 9* 7 5 | 8* 6* 3
. . 3 | 4 8 2* | 1 7 9*
8* 7 9 | 6* 3* 1 | 2* 4* .
---------+----------+---------
1* . . | . . . | 9 8* .
9 . . | 8 4 . | 6 1* 2
. 8* . | 1 . 9 | 5 3 .
```
Digits marked * were filled in by a player; the others were printed with the puzzle.
Show the answer
It's the blue 5 in row 4, column 2. Row 4 already has a printed 5 (row 4, column 6). A printed digit can't be wrong, so the blue one is. The right digit for that cell is 1.
## Want more boards like this?
We also make a Sudoku app for iPhone, iPad, Mac and Android. There are no ads in it at all, it works offline, and when you ask for a hint it shows you the technique instead of just filling in a number.
[App Store iPhone, iPad, Mac](https://apps.apple.com/app/apple-store/id6502922368?pt=125379530&ct=sudokuflow_web&mt=8) [Google Play Android](https://play.google.com/store/apps/details?id=com.rubigogames.sudoku&referrer=utm_source%3Dsudokuflow%26utm_medium%3Dweb%26utm_campaign%3Dsite)
Sudoku Flow is made by Rubigo Games, the developer of the Sudoku app recommended on this site.