Question 147
The sums of the three columns and of the three rows of the table are equal.
| 4 | 9 | 2 |
| :--- | :--- | :--- |
| 8 | 1 | 6 |
| 3 | 5 | 7 |
What is the smallest number of cells of the table that must be changed so that all six new sums are different from each other?
| 4 | 9 | 2 |
| :--- | :--- | :--- |
| 8 | 1 | 6 |
| 3 | 5 | 7 |
What is the smallest number of cells of the table that must be changed so that all six new sums are different from each other?