At least they got the 2 cents part right. Do you really want to have some fun? Some time when you are at a place like McDonalds (or any other place where you have a young cashier) wait for them to say, for instance, that will be $17.63. Then give them a $20 bill. After they have rung in $20 amount tendered, say, "Wait. Here is 13 cents." They will self implode.