The difference between 81 and 20 is: 
The difference between 76 and 35 is: 
The difference between 84 and 20 is: 
The difference between 81 and 20 is: 
The difference between 51 and 20 is: 
The difference between 81 and 40 is: 
The difference between 90 and 29 is: 
The difference between 81 and 20 is: 