Q: How much is 31 minus 20? A: 
Q: How much is 77 minus 11? A: 
Q: How much is 39 minus 20? A: 
Q: How much is 31 minus 20? A: 
Q: How much is 71 minus 20? A: 
Q: How much is 31 minus 20? A: 
Q: How much is 40 minus 29? A: 
Q: How much is 31 minus 20? A: 