Letter Sudoku Puzzle Logical Reasoning for Kids - Free Printable

This is a "Letter Sudoku" puzzle. The goal is to fill the 4x4 grid with the letters A, B, C, and D so that each letter appears exactly once in every row, every column, and every 2x2 sub-grid (box).

Let me solve this step by step.

Step 1: Analyze the given grid

The grid is:
```
Row 1: A _ D _
Row 2: _ B _ C
Row 3: C _ _ _
Row 4: _ D _ A
```

Step 2: Solve the puzzle using logic

I'll go cell by cell, looking for cells that have only one possible letter based on the row, column, and box constraints.

- Cell (1,2): Row 1 has A and D. Column 2 has B and D. Box 1 (top-left 2x2) has A and B. So, available letters are C (since A, B, D are already in row/col/box). Let's put C here.
- Cell (1,4): Row 1 has A, C, D. So, missing B. Column 4 has C and A. Box 2 (top-right 2x2) has D and C. So, B is the only option. Put B here.
- Cell (2,1): Row 2 has B and C. Column 1 has A and C. Box 1 has A, B, C. So, missing D. Put D here.
- Cell (2,3): Row 2 has D, B, C. So, missing A. Column 3 has D. Box 2 has D, C, B. So, A is the only option. Put A here.
- Cell (3,2): Row 3 has C. Column 2 has B, D, and we just put C in (1,2). So, column 2 has B, D, C. Missing A. Box 3 (bottom-left 2x2) has C and D. So, A is the only option. Put A here.
- Cell (3,3): Row 3 has C and A. Column 3 has D and A. Box 3 has C, D, A. So, missing B. Put B here.
- Cell (3,4): Row 3 has C, A, B. So, missing D. Column 4 has C, B, A. So, D is the only option. Put D here.
- Cell (4,1): Row 4 has D and A. Column 1 has A, D, C. Box 3 has C, D, A. So, missing B. Put B here.
- Cell (4,3): Row 4 has B, D, A. So, missing C. Column 3 has D, A, B. Box 4 (bottom-right 2x2) has C, A, D. So, C is the only option. Put C here.

Step 3: Final grid

After filling all cells, the solved grid is:
```
Row 1: A C D B
Row 2: D B A C
Row 3: C A B D
Row 4: B D C A
```

Let me verify:
- Each row has A, B, C, D.
- Each column has A, B, C, D.
- Each 2x2 box has A, B, C, D.

Everything checks out.

Final Answer

The completed Letter Sudoku puzzle is:

```
A C D B
D B A C
C A B D
B D C A
```