The difference between 31 and 31 is: 
The difference between 77 and 10 is: 
The difference between 34 and 31 is: 
The difference between 31 and 30 is: 
The difference between 91 and 31 is: 
The difference between 31 and 11 is: 
The difference between 30 and 33 is: 
The difference between 31 and 31 is: 