One day, I was going to school. I saw an old man. He said that he will pay me if I answered his question properly.
If we add 2 into 10 it will be 8, i.e. 10+2=8
If we subtract 2 from 10 it will be 12, i.e. 10-2=12
I forget that the old man was renovating his house. How is this possible?