Q: How much is 64 minus 40? A: 
Q: How much is 93 minus 24? A: 
Q: How much is 67 minus 40? A: 
Q: How much is 64 minus 43? A: 
Q: How much is 74 minus 40? A: 
Q: How much is 64 minus 20? A: 
Q: How much is 73 minus 49? A: 
Q: How much is 64 minus 40? A: 