The difference between 13 and 12 is: 
The difference between 40 and 35 is: 
The difference between 18 and 12 is: 
The difference between 13 and 12 is: 
The difference between 33 and 12 is: 
The difference between 13 and 12 is: 
The difference between 20 and 19 is: 
The difference between 13 and 12 is: 