Q: How much is 15 minus 13? A: 
Q: How much is 87 minus 59? A: 
Q: How much is 16 minus 13? A: 
Q: How much is 15 minus 14? A: 
Q: How much is 35 minus 13? A: 
Q: How much is 15 minus 13? A: 
Q: How much is 21 minus 19? A: 
Q: How much is 15 minus 13? A: 