[antiRepublicrat]

I’ve had cashiers get confused when I hand them $20.10 for an item that cost $5.05. It’s because I don’t have a nickel, but I’d rather have a ten, a five and a nickel than a ten, four ones and 95 cents change.

[Alia]

Yours is exactly what I'm talking about. And I don't mean arrogance. It's how you were taught math, that you do this.

Folks whose math education was purely long add/div, won't tend to do this. Their synapses have been trained a specific way. It's not necessarily that the person at the cash register is "dumb" at math. They were trained to a longer process in doing math.