The difference between 50 and 13 is: 
The difference between 81 and 33 is: 
The difference between 54 and 13 is: 
The difference between 50 and 10 is: 
The difference between 20 and 13 is: 
The difference between 50 and 33 is: 
The difference between 58 and 11 is: 
The difference between 50 and 13 is: 