## Criss Cross

### Problem 166

Published on Saturday, 3rd November 2007, 01:00 pm; Solved by 2570; Difficulty rating: 50%A 4x4 grid is filled with digits d, 0 ≤ d ≤ 9.

It can be seen that in the grid

6 3 3 0

5 0 4 3

0 7 1 4

1 2 4 5

the sum of each row and each column has the value 12. Moreover the sum of each diagonal is also 12.

In how many ways can you fill a 4x4 grid with the digits d, 0 ≤ d ≤ 9 so that each row, each column, and both diagonals have the same sum?