---
title: "Find the Mistake Level Up #15: 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 #15: play every level and see each answer."
url: https://sudokuflow.com/puzzles/level-up-15/
language: en
---
[Puzzles](https://sudokuflow.com/puzzles/) / Level Up #15
Level Up
# Level Up #15
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/fzNEGB8U2a4)
## Level 1 · 4×4
Tap the digit you think is wrong.
Level Up #15 · Level 1 · 4×4:
```text
3* . | 2 3
. 2 | 4* 1
------+------
. 3 | . 4*
4 . | 3* 2*
```
Digits marked * were filled in by a player; the others were printed with the puzzle.
Show the answer
It's the blue 3 in row 1, column 1. Row 1 already has a printed 3 (row 1, column 4). 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 #15 · Level 2 · 6×6:
```text
. 4* . | 1 2* .
5* . 1* | 6* 4 3
---------+---------
2* 3 4* | 5 . 1*
1 6 5 | 4 . 2*
---------+---------
. 1 3 | 2* . .
6 5 2 | 4* 1 .
```
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 6, column 4. Column 4 already has a printed 4 (row 4, column 4). A printed digit can't be wrong, so the blue one is. The right digit for that cell is 3.
## Level 3 · 9×9
Tap the digit you think is wrong.
Level Up #15 · Level 3 · 9×9:
```text
6* 2 5* | 7 3* 1 | 8 9 4
7* 3 1 | 9 . . | . . 5
8 9* 4 | 6* 2* 5* | 7 3* 1
---------+----------+---------
. 6 7* | 2 1* . | 9 . 8
. 1* 2* | 8* . 7 | . . 3*
. 4 8* | 5 . . | . 1 7
---------+----------+---------
1 5* 6* | 3* . 2 | 4 . 9
9* 8 3 | 4 . 6 | . . 2*
4 7 2 | 1* . . | 3 . 6
```
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 5, column 3. Column 3 already has a printed 2 (row 9, column 3). A printed digit can't be wrong, so the blue one is. The right digit for that cell is 9.
## 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.