It's Matchic!

Effect: You reveal how many matches were moved while your back was turned.

Secret: Secretly put a small pencil dot on a match, just below the head. Do this on all four sides of the match and then put it back in the box. When you show the trick, remove ten matches from the box and put them down in a row. The marked match must be placed at the left end of the row. Turn your back and ask someone to move any number of matches, one at a time, from the left end of the row to the right. When you turn around you have only to spot the position of the marked match and count from that to the right end of the row to know how many have been moved.