I made a resent purchase that came to $11.26. I handed the cashier a twenty, a one, a quarter and a penny. She handed me back the one, the quarter and the penny telling me the twenty will cover it. I stated that I would like an even $10.00 back and she answered that WE would know know what the change would be until she rang it up. I asked her to enter the $21.26 as for the amount tendered and we would see what happened. When the change amount $10.00 appeared she was completely surprised and said, how did I know that would happen. My wife was walking away fearing eye contact with anyone and I answered as I left with my 10 dollar bill, "Magic". Computers are wonderful but they are becoming necessary for way too much.