3 men* go to a restaurant…

and pay $30 for a meal.

The restaurant owner checks their bill and realises they have been overcharged by $5. He gives a waiter the money and instructs him to reimburse the three men. The waiter is a bit dodgy, so he pockets $2 for himself and gives each man back $1 each.

Each man has therefore paid $9 and the waiter has kept $2.

Given: $9 multiplied by 3 is $27 and then adding $2 makes $29 [(9 x 3) + 2 = 29], where did the other $1 go?
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* Feel free to substitute "women" if you are that PC.