Lucky I had that quarter

So, I'm at blockbuster renting the 1st two Pirates of the Caribbean movies (the third is available on PPV). The total rental fee comes to $5.25. I give the guy $20.25. He punches in $50.25 by mistake.

Uh oh. What now? How can he possibly make correct change now?

Several minutes of blank staring and inactivity ensue.

Oh, thank Todd! There's a calculator on hand. 20.25 - 5.25 = 15.00

Disaster averted.

How did people ever do this sort of thing without cash registers or calculators? Are you kidding me? Give me a freaking break.

I guess I should have used a credit card instead.