The 1 of 21 card trick is very simple to learn, but very difficult for your friend to figure out. This will create three columns of cards with seven cards in each column.
All cards are to be face-up.
Ask your friend to mentally pick one card out of the 21 shown. He is to remember the number and the suit of the card he picked throughout the trick. Ask him to tell you which column the card is in. It s important to remember to keep all the cards in each column in the order that you laid them down. After all 21 cards have been laid down, ask your friend which column the card is now in.