Q: How much is 78 minus 50? A: 
Q: How much is 97 minus 58? A: 
Q: How much is 79 minus 50? A: 
Q: How much is 78 minus 54? A: 
Q: How much is 68 minus 50? A: 
Q: How much is 78 minus 60? A: 
Q: How much is 86 minus 58? A: 
Q: How much is 78 minus 50? A: 