How to fill the number 1-9 in a 9-empty square box to make the sum of horizontal and vertical directions equal? Even squares can be filled with squares, such as 1-25, 1-49 and so on. Methods This paper introduces a method of days, which is called radish method. When filling in numbers, fill in the middle number in the middle of the square. 1 cannot be filled in the corner. Then follow the principle in turn: for the numbers on the side, the row is greater than 1 in the upper left, the column is greater than 1 in the lower right, excluding "upper left" and "lower right", greater than 1 in the lower right, and other numbers (numbers not on the side and numbers excluding upper left and lower right) are greater than 1 in the upper right. 1 in the upper left corner here refers to the number in the rightmost column, and the leftmost number in the previous row is more than1; Lower right 1 above. For example, 1-9,8 1 6357492 first fill in the numbers1and 5, and then1is 2 in the lower right, 2 in the upper left is 3, 3 is 4 in the lower right, 5 in the upper right, 6 in the upper right, and 7 in the lower right for lines without upper left. The same is true for 1-25 and 1-49.