Question 19
In the 4 by 4 square shown, I am filling in the 16 small squares with the numbers 1, 2, 3 and 4 so that each row and each column has one of each of these numbers. I have filled in some of the squares as shown. What do the two squares marked * add to?
| 1 | blank | * | blank |
|---|---|---|---|
| blank | blank | * | 4 |
| blank | blank | blank | 2 |
| 4 | 3 | 2 | 1 |
| 1 | blank | * | blank |
|---|---|---|---|
| blank | blank | * | 4 |
| blank | blank | blank | 2 |
| 4 | 3 | 2 | 1 |