The difference between 81 and 28 is: 
The difference between 78 and 40 is: 
The difference between 89 and 28 is: 
The difference between 81 and 20 is: 
The difference between 91 and 28 is: 
The difference between 81 and 28 is: 
The difference between 88 and 25 is: 
The difference between 81 and 28 is: 