The difference between 91 and 15 is: 
The difference between 61 and 55 is: 
The difference between 99 and 15 is: 
The difference between 91 and 10 is: 
The difference between 61 and 15 is: 
The difference between 91 and 75 is: 
The difference between 96 and 10 is: 
The difference between 91 and 15 is: 