The answer is: 8
because the sum of every row is equal to 15
1 + 5 + 6 + 3 = 15
4+ 8 +1 + 2 = 15
9+ 1 + 2 + 4 = 15
1 + 1 +6 + 7 = 15
The answer is: 8
because the sum of every row is equal to 15
1 + 5 + 6 + 3 = 15
4+ 8 +1 + 2 = 15
9+ 1 + 2 + 4 = 15
1 + 1 +6 + 7 = 15