The difference between 28 and 15 is: 
The difference between 45 and 25 is: 
The difference between 28 and 15 is: 
The difference between 28 and 17 is: 
The difference between 78 and 15 is: 
The difference between 28 and 15 is: 
The difference between 31 and 18 is: 
The difference between 28 and 15 is: 