The difference between 66 and 13 is: 
The difference between 99 and 42 is: 
The difference between 67 and 13 is: 
The difference between 66 and 11 is: 
The difference between 96 and 13 is: 
The difference between 66 and 33 is: 
The difference between 71 and 18 is: 
The difference between 66 and 13 is: 