The difference between 30 and 15 is: 
The difference between 71 and 17 is: 
The difference between 36 and 15 is: 
The difference between 30 and 10 is: 
The difference between 80 and 15 is: 
The difference between 30 and 15 is: 
The difference between 39 and 14 is: 
The difference between 30 and 15 is: 