A spectator is asked to take a $1 bill from their wallet and place it inside a small envelope, which is then sealed and signed by the spectator, eliminating any possibility for a switch. A deck of blank cards with numbers written on them is given to the participant to look through, and then is shuffled. A packet of these number cards is cut off the deck and handed to the participant (the performer never touches the cards again). The participant mixes the cards so that when they’re done, some of the cards will be face up and some will be face down. The cards are then spread and the face down cards are placed aside, leaving only the face up cards. The sealed, signed envelope is now opened and the borrowed bill is tipped out into the participant’s hands. The serial number of the bill is read aloud, and number-for-number it perfectly matches the numbers written on the cards selected by the spectator!
A hands-off mental miracle where the participant gets all the credit.