The difference between 81 and 79 is: 
The difference between 84 and 21 is: 
The difference between 89 and 79 is: 
The difference between 81 and 70 is: 
The difference between 91 and 79 is: 
The difference between 81 and 59 is: 
The difference between 83 and 71 is: 
The difference between 81 and 79 is: 