The difference between 98 and 18 is: 
The difference between 49 and 10 is: 
The difference between 99 and 18 is: 
The difference between 98 and 17 is: 
The difference between 68 and 18 is: 
The difference between 98 and 28 is: 
The difference between 91 and 13 is: 
The difference between 98 and 18 is: 