You can put this solution on YOUR website! let the numbers be x & y
Two numbers differ by 13.
x-y =13-----------------------1
Their sum is 29.
x+y =29 ---------------------2
Add equation 1 & 2
2x = 42
x =42/2
x =21
plug x in equation 2
x+y =29
21+y=29
y = 29-21
y =8
The numbers are 21 & 8