The difference between 99 and 13 is: 
The difference between 91 and 76 is: 
The difference between 94 and 13 is: 
The difference between 99 and 11 is: 
The difference between 89 and 13 is: 
The difference between 99 and 73 is: 
The difference between 103 and 17 is: 
The difference between 99 and 13 is: 