The difference between 77 and 15 is: 
The difference between 52 and 51 is: 
The difference between 79 and 15 is: 
The difference between 77 and 11 is: 
The difference between 57 and 15 is: 
The difference between 77 and 65 is: 
The difference between 80 and 18 is: 
The difference between 77 and 15 is: 