The difference between 20 and 15 is: 
The difference between 40 and 13 is: 
The difference between 26 and 15 is: 
The difference between 20 and 10 is: 
The difference between 50 and 15 is: 
The difference between 20 and 15 is: 
The difference between 28 and 13 is: 
The difference between 20 and 15 is: 