List the sum of the numbers on the four corners of the box in each row and column and the numbers in the circle:

5+3+2+ 1= 1 1 16 8+6+5+3=22 17 4+2+7+9=22 27 6+8+7+2=23 18

3+5+ 1+4= 13 18 6+2+7+3= 18 13 5+9+4+ 1= 19 24 6+8+3+2= 19 ?

It can be seen that the difference of the sum of the numbers of the four corners of two boxes in each column is equal to the difference of the numbers of the circle.

The first column:13-11=18-16 = 2

Column 2: 22-18 =17-13 = 4.

Column 3: 22- 19=27-24=3.

The fourth column: 23- 19=4. = 18-4= 14