Q: What is 21 minus 13? A: 
Q: What is 49 minus 22? A: 
Q: What is 27 minus 13? A: 
Q: What is 21 minus 10? A: 
Q: What is 81 minus 13? A: 
Q: What is 21 minus 13? A: 
Q: What is 28 minus 10? A: 
Q: What is 21 minus 13? A: 