— The buttons correspond to different coin denominations

— Use the buttons to reduce the amount to zero

— If you overpay, the amount will turn red, this will count as an incorrect answer

— If you reduce the amount to zero, the amount will turn green, this will count as a correct answer

— The next amount will be generated automatically

— Use the Easy, Medium, and Hard buttons to control difficulty

— The bar shows the ratio of correct to incorrect answers