Task 1.4. A $4 \times 4$ table is divided into four $2 \times 2$ squares.

Vika wrote 4 ones, 4 twos, 4 threes, and 4 fours in the cells of the table such that in each column, each row, and each $2 \times 2$ square, all numbers are different.

The hooligan Andrey erased some of the numbers. Help Vika restore which cells contained fours.

|  | 1 | 2 | 3 | 4 |
| :---: | :---: | :---: | :---: | :---: |
| $A$ |  |  | 1 |  |
| $B$ |  | 3 |  |  |
| c |  |  |  |  |
| $D$ |  |  | 2 | 1 |

Construct the correspondence

- In row $A$, the four is in
- In row $B$, the four is in
- In row $C$, the four is in
- In row $D$, the four is in
- column 1.
- column 2.
- column 3.
- column 4.
Answer: $A-1, B-3, C-4, D-2$.

## Grade 7, Problem 2