The process of answering the third question on page 1 15 in the second volume of seventh grade mathematics.
The second volume of the seventh grade of People's Education Edition sets one digit as X, ten digits as Y, and hundred digits as Z, X+z=y 7z=x+y+2 x+y+z= 14. Substitute x+z=y into x+y+z= 14 to get 2y= 14, so y=7 substitute y=7 into x+z=y, 7Z =