An introductory presentation for the Fred Kaps $11 Bill Trick: First tell the old story about the restaurant and the 3 guests. The bill for the 3 customers is $30. Each pays $10. Later, in the kitchen, the owner explains that the bill is actually only $25 and not $30. A mistake has been made. So the chef gives the waiter 5 $1 bills to give back to the guests.
But the waiter is dishonest and puts 2 $1 bills in his pocket. He gives $1 back to each guest. So each diner has really only paid $9. That makes $27. Plus the two dollars the waiter stole = $29. WHERE is the one dollar? Has it disappeared?
Then perform the Fred Kaps $11 Bill Trick as described in the original manuscript by Anthony Brahams.