1) Enter the amount of coins and dollars in you wallet in the respective boxes.
2) Click "Count now!" to find the total of your cash.
3) For a quick "Pop-Up" version, click the "Pop-Up" button.
What you just did was use the "natural calculator" built into your computer. It took the number of coins/bills and multiplied it by its real value. Then it added it all up. You can see the unsolvable bug in the program if you enter only a number of dimes.