Q: How much is 64 minus 21? A: 
Q: How much is 77 minus 47? A: 
Q: How much is 66 minus 21? A: 
Q: How much is 64 minus 20? A: 
Q: How much is 94 minus 21? A: 
Q: How much is 64 minus 21? A: 
Q: How much is 71 minus 28? A: 
Q: How much is 64 minus 21? A: 