a+(a-2)+(a+2)+(a- 12)+(a+ 12)= 5a;
(2)5a=2020,
a=404,
This is impossible, because a should be an odd number;
(3)5a=365,
a=73,
And because 73÷ 12=6. 1, 73 is in the first column of the seventh row.
Because we set a as the number in the middle of the cross box, it is impossible.