1. Attach a full box of matches to your wrist with a rubber band and hide the box in your shirtsleeve.

2. Show your friends another matchbox and shake it.

3. Ask them to guess how many matches are in the box.

4. When they have guessed the number of matches, slide open the box to reveal that it is empty!

When you shook the box, they were hearing the matches in the box strapped to your wrist!