The sum of each row and column is 15, and the sum of * * 6 rows and columns = 15*6=90.

on the other hand

1+2+。 . . +9=45, so each number is added exactly twice, and the position of each number in this square doesn't matter. Therefore, when building, just follow the following methods:

The first line randomly takes three numbers that add up to 15, and then the second line takes three books that add up to 15. The two numbers added up in each column are not equal, so the third line makes up the rest.

For example, the following:

1,5,9

8,3,4

6,7,2