The difference between 91 and 17 is: 
The difference between 96 and 66 is: 
The difference between 98 and 17 is: 
The difference between 91 and 10 is: 
The difference between 31 and 17 is: 
The difference between 91 and 87 is: 
The difference between 97 and 13 is: 
The difference between 91 and 17 is: 