Most of the time for official coin tosses the interested party calls the result while the coin is in the air. Often, the coin is allowed to land on the ground to prevent tampering. Assuming that you are in a flipping situation where you are flipping it into your hand and calling it when it gets to the hand, it is pretty easy to guess the result accurately. This video will show you how to do so by rubbing the coin quickly to determine whether it is bumpy-side (tails) up or smooth-side (heads).
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