**D**avid's
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You 'll see below a certain amount of coins displayed so as to form a 9. Pick out an amount of coins superior to the amount of coins forming the tail of number 9.

Count this sum of coins starting at the coin at the very end of the tail of number 9. Call it coin 1. Keep counting until you get on a coin of the circle formed by number 9. Make sure you move on the circle counterclockwise.

Once you get on that coin of the circle, count the same sum but move clockwise and on the circle only. Count 1 on the coin where you arrived previously.

Put a finger on the coin where you just arrived.

An example ?Clickhere..