If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
The farmer has been kidnapped by the evil rat dentist! Help courage save him by cracking the door codes. Courage knows tha code, but can't reach the control panel, so he is going to have to give you clues to help you work out which buttons to press, If you get them all right you will rescue the farmer again.
Use mouse to press the numbers.