A deaf and mute man goes to the train station. Tickets for the train are 50 cents each. The man goes to the ticket booth and hands the man inside just a dollar. The man in the booth hands him two tickets.
How did the man in the booth know to give him two tickets without even looking at him?
The deaf and mute man gave him four quarters, so the man in the booth knew he wanted several tickets. Otherwise, he would have given him two quarters. This would work with any change equaling 50 cents.