This is a highly fooling effect for magicians.
Two decks are introduced, and the spectator freely chooses one and freely selects a card.
The spectator then takes the other deck and freely cuts it into three packets. No sleight of hand is used—the three packets are entirely the spectator's cuts.
The three cut-to cards not only reveal the identity of the selection, but their values also add up to the exact position of the selected card.
Simple setup, two ordinary decks, no gimmicks.
See the performance video for the complete effect.
