Medium Difficulty Sudoku Puzzles for Kids - Free Printable Worksheets - Free Printable

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

Initial Puzzle:

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

Step-by-Step Solution:

#### Step 1: Fill in obvious numbers
We start by looking for rows, columns, or boxes where only one number can fit in a particular cell.

1. Row 1, Column 9: The number 9 is already in the top-right box, so the only possible number for the empty cell in Row 1, Column 9 is 5.
```
4 _ _ | 2 _ _ | 1 9 5
```

2. Row 3, Column 8: The number 8 is already in the middle-right box, so the only possible number for the empty cell in Row 3, Column 8 is 5.
```
_ _ _ | 3 5 1 | _ 5 6
```

3. Row 6, Column 9: The number 9 is already in the bottom-right box, so the only possible number for the empty cell in Row 6, Column 9 is 9.
```
_ _ _ | _ _ _ | _ _ 9
```

#### Step 2: Use elimination and logic
We continue filling in cells by eliminating possibilities based on the rules of Sudoku.

4. Row 2, Column 1: The number 7 is the only missing number in the top-left box that can fit in Row 2, Column 1.
```
7 _ _ | 3 5 1 | _ 8 6
```

5. Row 3, Column 1: The number 8 is the only missing number in the top-left box that can fit in Row 3, Column 1.
```
8 3 1 | _ _ _ | _ _ _
```

6. Row 4, Column 1: The number 6 is the only missing number in the middle-left box that can fit in Row 4, Column 1.
```
6 _ 9 | 4 _ _ | _ 7 _
```

7. Row 5, Column 3: The number 8 is the only missing number in the middle-center box that can fit in Row 5, Column 3.
```
9 4 8 | _ _ 7 | _ _ _
```

8. Row 7, Column 1: The number 3 is the only missing number in the bottom-left box that can fit in Row 7, Column 1.
```
3 _ 2 | _ _ _ | _ 8 9
```

9. Row 8, Column 3: The number 5 is the only missing number in the bottom-center box that can fit in Row 8, Column 3.
```
4 2 5 | 1 6 9 | _ 4 1
```

#### Step 3: Continue filling in cells
We continue this process, using elimination and logic to fill in more cells.

10. Row 1, Column 3: The number 3 is the only missing number in the top-left box that can fit in Row 1, Column 3.
```
4 _ 3 | 2 _ _ | 1 9 5
```

11. Row 1, Column 5: The number 8 is the only missing number in the top-middle box that can fit in Row 1, Column 5.
```
4 _ 3 | 2 8 _ | 1 9 5
```

12. Row 1, Column 6: The number 7 is the only missing number in the top-right box that can fit in Row 1, Column 6.
```
4 _ 3 | 2 8 7 | 1 9 5
```

13. Row 2, Column 6: The number 9 is the only missing number in the top-right box that can fit in Row 2, Column 6.
```
7 _ _ | 3 5 9 | _ 8 6
```

14. Row 2, Column 3: The number 2 is the only missing number in the top-middle box that can fit in Row 2, Column 3.
```
7 _ 2 | 3 5 9 | _ 8 6
```

15. Row 2, Column 2: The number 4 is the only missing number in the top-middle box that can fit in Row 2, Column 2.
```
7 4 2 | 3 5 9 | _ 8 6
```

16. Row 2, Column 1: The number 1 is the only missing number in the top-left box that can fit in Row 2, Column 1.
```
7 4 2 | 3 5 9 | _ 8 6
```

17. Row 3, Column 5: The number 6 is the only missing number in the top-middle box that can fit in Row 3, Column 5.
```
8 3 1 | _ 6 _ | _ 5 9
```

18. Row 3, Column 6: The number 4 is the only missing number in the top-right box that can fit in Row 3, Column 6.
```
8 3 1 | _ 6 4 | _ 5 9
```

19. Row 3, Column 4: The number 7 is the only missing number in the top-middle box that can fit in Row 3, Column 4.
```
8 3 1 | 7 6 4 | _ 5 9
```

20. Row 4, Column 5: The number 5 is the only missing number in the middle-center box that can fit in Row 4, Column 5.
```
6 _ 9 | 4 5 _ | _ 7 _
```

21. Row 4, Column 6: The number 3 is the only missing number in the middle-right box that can fit in Row 4, Column 6.
```
6 _ 9 | 4 5 3 | _ 7 _
```

22. Row 4, Column 2: The number 1 is the only missing number in the middle-left box that can fit in Row 4, Column 2.
```
6 1 9 | 4 5 3 | _ 7 _
```

23. Row 4, Column 4: The number 2 is the only missing number in the middle-center box that can fit in Row 4, Column 4.
```
6 1 9 | 4 5 3 | _ 7 _
```

24. Row 4, Column 7: The number 8 is the only missing number in the middle-right box that can fit in Row 4, Column 7.
```
6 1 9 | 4 5 3 | 8 7 _
```

25. Row 4, Column 9: The number 2 is the only missing number in the middle-right box that can fit in Row 4, Column 9.
```
6 1 9 | 4 5 3 | 8 7 2
```

26. Row 5, Column 1: The number 9 is the only missing number in the middle-left box that can fit in Row 5, Column 1.
```
9 4 8 | _ _ 7 | _ _ _
```

27. Row 5, Column 2: The number 3 is the only missing number in the middle-left box that can fit in Row 5, Column 2.
```
9 4 8 | _ _ 7 | _ _ _
```

28. Row 5, Column 4: The number 1 is the only missing number in the middle-center box that can fit in Row 5, Column 4.
```
9 4 8 | 1 _ 7 | _ _ _
```

29. Row 5, Column 5: The number 2 is the only missing number in the middle-center box that can fit in Row 5, Column 5.
```
9 4 8 | 1 2 7 | _ _ _
```

30. Row 5, Column 7: The number 6 is the only missing number in the middle-right box that can fit in Row 5, Column 7.
```
9 4 8 | 1 2 7 | 6 _ _
```

31. Row 5, Column 8: The number 3 is the only missing number in the middle-right box that can fit in Row 5, Column 8.
```
9 4 8 | 1 2 7 | 6 3 _
```

32. Row 5, Column 9: The number 5 is the only missing number in the middle-right box that can fit in Row 5, Column 9.
```
9 4 8 | 1 2 7 | 6 3 5
```

33. Row 6, Column 1: The number 5 is the only missing number in the middle-left box that can fit in Row 6, Column 1.
```
5 _ _ | _ _ _ | _ _ 9
```

34. Row 6, Column 2: The number 7 is the only missing number in the middle-left box that can fit in Row 6, Column 2.
```
5 7 _ | _ _ _ | _ _ 9
```

35. Row 6, Column 3: The number 4 is the only missing number in the middle-left box that can fit in Row 6, Column 3.
```
5 7 4 | _ _ _ | _ _ 9
```

36. Row 6, Column 4: The number 8 is the only missing number in the middle-center box that can fit in Row 6, Column 4.
```
5 7 4 | 8 _ _ | _ _ 9
```

37. Row 6, Column 5: The number 3 is the only missing number in the middle-center box that can fit in Row 6, Column 5.
```
5 7 4 | 8 3 _ | _ _ 9
```

38. Row 6, Column 6: The number 6 is the only missing number in the middle-center box that can fit in Row 6, Column 6.
```
5 7 4 | 8 3 6 | _ _ 9
```

39. Row 6, Column 7: The number 2 is the only missing number in the middle-right box that can fit in Row 6, Column 7.
```
5 7 4 | 8 3 6 | 2 _ 9
```

40. Row 6, Column 8: The number 1 is the only missing number in the middle-right box that can fit in Row 6, Column 8.
```
5 7 4 | 8 3 6 | 2 1 9
```

41. Row 7, Column 3: The number 2 is the only missing number in the bottom-left box that can fit in Row 7, Column 3.
```
3 _ 2 | _ _ _ | _ 8 9
```

42. Row 7, Column 4: The number 5 is the only missing number in the bottom-center box that can fit in Row 7, Column 4.
```
3 _ 2 | 5 _ _ | _ 8 9
```

43. Row 7, Column 5: The number 1 is the only missing number in the bottom-center box that can fit in Row 7, Column 5.
```
3 _ 2 | 5 1 _ | _ 8 9
```

44. Row 7, Column 6: The number 4 is the only missing number in the bottom-center box that can fit in Row 7, Column 6.
```
3 _ 2 | 5 1 4 | _ 8 9
```

45. Row 7, Column 7: The number 7 is the only missing number in the bottom-right box that can fit in Row 7, Column 7.
```
3 _ 2 | 5 1 4 | 7 8 9
```

46. Row 7, Column 2: The number 8 is the only missing number in the bottom-left box that can fit in Row 7, Column 2.
```
3 8 2 | 5 1 4 | 7 8 9
```

47. Row 7, Column 1: The number 6 is the only missing number in the bottom-left box that can fit in Row 7, Column 1.
```
3 8 2 | 5 1 4 | 7 8 9
```

48. Row 8, Column 1: The number 4 is the only missing number in the bottom-left box that can fit in Row 8, Column 1.
```
4 2 5 | 1 6 9 | _ 4 1
```

49. Row 8, Column 2: The number 2 is the only missing number in the bottom-center box that can fit in Row 8, Column 2.
```
4 2 5 | 1 6 9 | _ 4 1
```

50. Row 8, Column 3: The number 5 is the only missing number in the bottom-center box that can fit in Row 8, Column 3.
```
4 2 5 | 1 6 9 | _ 4 1
```

51. Row 8, Column 4: The number 1 is the only missing number in the bottom-center box that can fit in Row 8, Column 4.
```
4 2 5 | 1 6 9 | _ 4 1
```

52. Row 8, Column 5: The number 6 is the only missing number in the bottom-center box that can fit in Row 8, Column 5.
```
4 2 5 | 1 6 9 | _ 4 1
```

53. Row 8, Column 6: The number 9 is the only missing number in the bottom-center box that can fit in Row 8, Column 6.
```
4 2 5 | 1 6 9 | _ 4 1
```

54. Row 8, Column 7: The number 3 is the only missing number in the bottom-right box that can fit in Row 8, Column 7.
```
4 2 5 | 1 6 9 | 3 4 1
```

55. Row 8, Column 8: The number 4 is the only missing number in the bottom-right box that can fit in Row 8, Column 8.
```
4 2 5 | 1 6 9 | 3 4 1
```

56. Row 8, Column 9: The number 1 is the only missing number in the bottom-right box that can fit in Row 8, Column 9.
```
4 2 5 | 1 6 9 | 3 4 1
```

57. Row 9, Column 1: The number 1 is the only missing number in the bottom-left box that can fit in Row 9, Column 1.
```
1 6 _ | _ 8 _ | 7 _ _
```

58. Row 9, Column 2: The number 6 is the only missing number in the bottom-left box that can fit in Row 9, Column 2.
```
1 6 _ | _ 8 _ | 7 _ _
```

59. Row 9, Column 3: The number 7 is the only missing number in the bottom-left box that can fit in Row 9, Column 3.
```
1 6 7 | _ 8 _ | 7 _ _
```

60. Row 9, Column 4: The number 2 is the only missing number in the bottom-center box that can fit in Row 9, Column 4.
```
1 6 7 | 2 8 _ | 7 _ _
```

61. Row 9, Column 5: The number 8 is the only missing number in the bottom-center box that can fit in Row 9, Column 5.
```
1 6 7 | 2 8 _ | 7 _ _
```

62. Row 9, Column 6: The number 5 is the only missing number in the bottom-center box that can fit in Row 9, Column 6.
```
1 6 7 | 2 8 5 | 7 _ _
```

63. Row 9, Column 7: The number 4 is the only missing number in the bottom-right box that can fit in Row 9, Column 7.
```
1 6 7 | 2 8 5 | 7 4 _
```

64. Row 9, Column 8: The number 9 is the only missing number in the bottom-right box that can fit in Row 9, Column 8.
```
1 6 7 | 2 8 5 | 7 4 9
```

65. Row 9, Column 9: The number 3 is the only missing number in the bottom-right box that can fit in Row 9, Column 9.
```
1 6 7 | 2 8 5 | 7 4 3
```

Final Solution:

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

6 1 9 | 4 5 3 | 8 7 2
9 4 8 | 1 2 7 | 6 3 5
5 7 4 | 8 3 6 | 2 1 9

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

Thus, the final answer is:
\[
\boxed{
\begin{array}{|3{c}|3{c}|3{c}|}
\hline
4 & 7 & 3 & 2 & 8 & 6 & 1 & 9 & 5 \\
7 & 4 & 2 & 3 & 5 & 9 & 8 & 8 & 6 \\
8 & 3 & 1 & 7 & 6 & 4 & 9 & 5 & 2 \\
\hline
6 & 1 & 9 & 4 & 5 & 3 & 8 & 7 & 2 \\
9 & 4 & 8 & 1 & 2 & 7 & 6 & 3 & 5 \\
5 & 7 & 4 & 8 & 3 & 6 & 2 & 1 & 9 \\
\hline
3 & 8 & 2 & 5 & 1 & 4 & 7 & 8 & 9 \\
4 & 2 & 5 & 1 & 6 & 9 & 3 & 4 & 1 \\
1 & 6 & 7 & 2 & 8 & 5 & 7 & 4 & 3 \\
\hline
\end{array}
}
\]