One of the 12 gold coins is a counterfeit. The counterfeit coin may be heavier or lighter than a genuine gold coin. How many trials do you need to find the fake one? Place the coins on both sides of the scale, press the golden round button to weigh. When you have found the fake coin, place it in the red box and click the red button to check. Good luck!
I can find the fake coin weighing a maximum of 3 times, can you?