The difference between 21 and 13 is: 
The difference between 86 and 69 is: 
The difference between 26 and 13 is: 
The difference between 21 and 10 is: 
The difference between 31 and 13 is: 
The difference between 21 and 13 is: 
The difference between 28 and 10 is: 
The difference between 21 and 13 is: 