The difference between 99 and 69 is: 
The difference between 20 and 11 is: 
The difference between 99 and 69 is: 
The difference between 99 and 61 is: 
The difference between 89 and 69 is: 
The difference between 99 and 79 is: 
The difference between 91 and 64 is: 
The difference between 99 and 69 is: 