The difference between 31 and 20 is: 
The difference between 71 and 48 is: 
The difference between 32 and 20 is: 
The difference between 31 and 20 is: 
The difference between 51 and 20 is: 
The difference between 31 and 10 is: 
The difference between 40 and 29 is: 
The difference between 31 and 20 is: 