Psychic Coin Challenge
A spectator hides a number of coins in his/her hand, and the remaining coins are covered with a cup. Without touching the cup and without asking any questions, the magician knows how many coins the spectator has in his/her hand, even though he was not in the room while the coins were removed.
You can also view this trick on YouTube at https://youtu.be/W4PPfvr-8Ww
You can see all the previous magic lessons here.