I was asked a question the other day...

About midway through my shift, a coworker picked up a scientific calculator, and started asking me some math questions.... square root of 80 (didn't know off the top of my head, beyond 8.- something), what's pi (surprised I knew it to 5 decimal places), etc. I then threw a couple more in, like what are the sine/cosine of 45, etc. Another coworker chimed in with, "what's two plus two?"

Both the original coworker and I looked at her and said, "five."

Later in the evening, she asked me how that equation works. I tried, in vain, to explain that except in the cases of geometry and the straight arithmetic we were taught in elementary school, there are usually extenuating circumstances in the middle that tend to change the answer from what is expected. This reminded me of an old Sidney Harris cartoon from the New Yorker which has always been one of my favorites: