The difference between 81 and 24 is: 
The difference between 90 and 45 is: 
The difference between 85 and 24 is: 
The difference between 81 and 20 is: 
The difference between 71 and 24 is: 
The difference between 81 and 54 is: 
The difference between 88 and 21 is: 
The difference between 81 and 24 is: 