This was a test for the attendant at the Wal-Mart Subway in Farmington, CT. He first completed the sale and opened the register before I gave him any money. He asked for $4.12 and I gave him a twenty and a quarter. He then did the above calculations with me standing there chanting $16.13, and the register open. He first wanted to give me the wrong change, then had to recalculate for the right change. After that was straightened out, he was going to keep my receipt with my coupon stapled to it. (Oh yeah, it took him a few tries to subtract fifty cents on the register.)
Stay in school, kids, or you'll end up taking ten minutes subtracting one number on a calculator in a Subway in Wal-Mart.