The difference between 27 and 13 is: 
The difference between 71 and 20 is: 
The difference between 27 and 13 is: 
The difference between 27 and 13 is: 
The difference between 27 and 13 is: 
The difference between 27 and 13 is: 
The difference between 31 and 17 is: 
The difference between 27 and 13 is: 