Printable Sudoku - 100+ Puzzles From Easy To Hard - World of ... - Free Printable

To solve the Sudoku puzzle, we need to fill in the grid such that each row, each column, and each of the nine 3x3 subgrids contain all the digits from 1 to 9 exactly once. Let's go through the solution step by step.

Initial Grid:

```
+-------+-------+-------+
| 8 4 | 2 | |
| | | 4|
| | 2 | 3 8|
+-------+-------+-------+
| 4 | | |
| 9 | 1 5 | |
| 9 | | 5|
+-------+-------+-------+
| 2 | 3 9 | 4 6 1 |
| 4 | 5 | 9|
+-------+-------+-------+
```

Step-by-Step Solution:

#### Step 1: Fill in obvious numbers
We start by looking for cells where only one number can fit based on the existing numbers in the row, column, and box.

1. Row 2, Column 9: The number 4 is already in the grid, so we place it.
```
+-------+-------+-------+
| 8 4 | 2 | |
| | | 4|
| | 2 | 3 8|
+-------+-------+-------+
| 4 | | |
| 9 | 1 5 | |
| 9 | | 5|
+-------+-------+-------+
| 2 | 3 9 | 4 6 1 |
| 4 | 5 | 9|
+-------+-------+-------+
```

2. Row 3, Column 8: The number 8 is already in the grid, so we place it.
```
+-------+-------+-------+
| 8 4 | 2 | |
| | | 4|
| | 2 | 3 8|
+-------+-------+-------+
| 4 | | |
| 9 | 1 5 | |
| 9 | | 5|
+-------+-------+-------+
| 2 | 3 9 | 4 6 1 |
| 4 | 5 | 9|
+-------+-------+-------+
```

#### Step 2: Use elimination and logic
We continue by using the process of elimination and logical deduction to fill in more numbers.

3. Row 1, Column 1: The only number that fits is 7.
```
+-------+-------+-------+
| 7 8 4 | 2 | |
| | | 4|
| | 2 | 3 8|
+-------+-------+-------+
| 4 | | |
| 9 | 1 5 | |
| 9 | | 5|
+-------+-------+-------+
| 2 | 3 9 | 4 6 1 |
| 4 | 5 | 9|
+-------+-------+-------+
```

4. Row 1, Column 5: The only number that fits is 6.
```
+-------+-------+-------+
| 7 8 4 | 2 6 | |
| | | 4|
| | 2 | 3 8|
+-------+-------+-------+
| 4 | | |
| 9 | 1 5 | |
| 9 | | 5|
+-------+-------+-------+
| 2 | 3 9 | 4 6 1 |
| 4 | 5 | 9|
+-------+-------+-------+
```

5. Row 1, Column 9: The only number that fits is 5.
```
+-------+-------+-------+
| 7 8 4 | 2 6 | 5|
| | | 4|
| | 2 | 3 8|
+-------+-------+-------+
| 4 | | |
| 9 | 1 5 | |
| 9 | | 5|
+-------+-------+-------+
| 2 | 3 9 | 4 6 1 |
| 4 | 5 | 9|
+-------+-------+-------+
```

#### Step 3: Continue filling in the grid
We continue this process, filling in numbers based on the rules of Sudoku.

6. Row 2, Column 1: The only number that fits is 6.
```
+-------+-------+-------+
| 7 8 4 | 2 6 | 5|
| 6 | | 4|
| | 2 | 3 8|
+-------+-------+-------+
| 4 | | |
| 9 | 1 5 | |
| 9 | | 5|
+-------+-------+-------+
| 2 | 3 9 | 4 6 1 |
| 4 | 5 | 9|
+-------+-------+-------+
```

7. Row 2, Column 5: The only number that fits is 5.
```
+-------+-------+-------+
| 7 8 4 | 2 6 | 5|
| 6 | | 5 4|
| | 2 | 3 8|
+-------+-------+-------+
| 4 | | |
| 9 | 1 5 | |
| 9 | | 5|
+-------+-------+-------+
| 2 | 3 9 | 4 6 1 |
| 4 | 5 | 9|
+-------+-------+-------+
```

8. Row 2, Column 3: The only number that fits is 3.
```
+-------+-------+-------+
| 7 8 4 | 2 6 | 5|
| 6 | 3 | 5 4|
| | 2 | 3 8|
+-------+-------+-------+
| 4 | | |
| 9 | 1 5 | |
| 9 | | 5|
+-------+-------+-------+
| 2 | 3 9 | 4 6 1 |
| 4 | 5 | 9|
+-------+-------+-------+
```

#### Step 4: Solve the rest of the grid
We continue this process until the entire grid is filled. After solving, the completed grid looks like this:

```
+-------+-------+-------+
| 7 8 4 | 9 2 6 | 1 3 5 |
| 6 5 3 | 8 7 1 | 9 2 4 |
| 1 9 2 | 4 5 3 | 6 7 8 |
+-------+-------+-------+
| 4 7 6 | 2 8 9 | 5 1 3 |
| 2 3 9 | 1 5 7 | 8 4 6 |
| 9 1 5 | 6 3 4 | 7 8 2 |
+-------+-------+-------+
| 5 2 8 | 7 9 6 | 4 6 1 |
| 3 4 1 | 5 6 8 | 2 9 7 |
| 8 6 7 | 3 4 2 | 5 1 9 |
+-------+-------+-------+
```

Final Answer:

```
\boxed{
\begin{array}{|3{||c|}3{||c|}3{||c|}}
\hline
7 & 8 & 4 & 9 & 2 & 6 & 1 & 3 & 5 \\
\hline
6 & 5 & 3 & 8 & 7 & 1 & 9 & 2 & 4 \\
\hline
1 & 9 & 2 & 4 & 5 & 3 & 6 & 7 & 8 \\
\hline
4 & 7 & 6 & 2 & 8 & 9 & 5 & 1 & 3 \\
\hline
2 & 3 & 9 & 1 & 5 & 7 & 8 & 4 & 6 \\
\hline
9 & 1 & 5 & 6 & 3 & 4 & 7 & 8 & 2 \\
\hline
5 & 2 & 8 & 7 & 9 & 6 & 4 & 6 & 1 \\
\hline
3 & 4 & 1 & 5 & 6 & 8 & 2 & 9 & 7 \\
\hline
8 & 6 & 7 & 3 & 4 & 2 & 5 & 1 & 9 \\
\hline
\end{array}
}
```