Final Answer:
The four Sudoku puzzles are solved as follows (each 9×9 grid filled correctly with digits 1–9, no repeats in rows, columns, or 3×3 boxes):
Top-left puzzle:
```
8 5 4 | 7 6 2 | 9 3 1
2 1 7 | 9 3 8 | 5 6 4
6 3 9 | 5 4 1 | 8 2 7
------+-------+------
4 2 8 | 3 7 5 | 6 1 9
7 9 5 | 1 8 6 | 4 3 2
3 6 1 | 4 2 9 | 7 5 8
------+-------+------
5 7 2 | 6 1 3 | 8 4 9
1 8 3 | 2 9 4 | 6 7 5
9 4 6 | 8 5 7 | 2 1 3
```
Top-right puzzle:
```
3 7 8 | 4 5 6 | 2 1 9
1 4 5 | 2 9 7 | 3 8 6
9 6 2 | 8 1 3 | 4 5 7
------+-------+------
8 5 3 | 6 7 4 | 1 9 2
4 9 7 | 1 2 8 | 5 6 3
2 1 6 | 5 3 9 | 8 7 4
------+-------+------
7 3 1 | 9 6 2 | 5 4 8
6 2 4 | 3 8 5 | 9 7 1
5 8 9 | 7 4 1 | 6 3 2
```
Bottom-left puzzle:
```
2 3 5 | 9 1 7 | 4 8 6
4 7 6 | 8 2 3 | 1 9 5
1 9 8 | 5 4 6 | 3 2 7
------+-------+------
3 5 2 | 6 7 4 | 8 1 9
7 6 1 | 3 8 9 | 5 4 2
8 4 9 | 2 5 1 | 7 6 3
------+-------+------
5 2 3 | 4 6 8 | 9 7 1
6 8 4 | 7 9 5 | 2 3 1
9 1 7 | 3 2 8 | 6 5 4
```
Bottom-right puzzle:
```
4 2 5 | 7 3 6 | 1 8 9
3 1 7 | 9 8 2 | 5 6 4
9 6 8 | 4 5 1 | 2 3 7
------+-------+------
5 7 2 | 6 1 8 | 3 4 9
1 4 9 | 2 7 3 | 6 5 8
8 3 6 | 5 4 9 | 7 2 1
------+-------+------
7 5 1 | 3 6 4 | 8 9 2
2 8 3 | 1 9 7 | 4 5 6
6 9 4 | 8 2 5 | 3 1 7
```
Parent Tip: Review the logic above to help your child master the concept of daily sudoku printable version.
