The difference between 68 and 66 is: 
The difference between 72 and 67 is: 
The difference between 68 and 66 is: 
The difference between 68 and 63 is: 
The difference between 78 and 66 is: 
The difference between 68 and 16 is: 
The difference between 71 and 69 is: 
The difference between 68 and 66 is: 