Two duplicate sets of cards (with different backs) are shown. One set is face up and the other face down. The faces show the four different suits of the same value and the backs have the numerals 1, 2, 3, and 4. A prediction envelope is handed to a spectator. One of each set is selected with the understanding that the opposite sides will match the card in the prediction envelope. When the prediction card is removed, the face is different than the original cards and the back has the number, 7. You claim there is only one thing to do - use magic. Both cards are turned and the face of the card turned matches the prediction face. The back of the second card turned has the number, 7.