Magician lays out 11 cards and asks a volunteer to move several cards over from the right side to the left side while the magician's back is to the cards so he/she doesn't see how many.
Then, when the volunteer is done the magician turns back around. He/she waves his hand over the cards and turns over one of the cards. The number on the card is the number of cards the volunteer moved.
(or have the magic puppet wave its hand over the card and then whisper to you to turn it over.)
11 cards from a regular deck of 52. Take 1 joker, an ace and all the numbers up to 10.
Lay out the cards face down in this order: 6 5 4 3 2 A J 10 9 8 7 (A is Ace and J is Joker).
Then have someone move the cards one at a time from right to left.
Say they moved three cards (the magician wouldn't know it though) the position of the cards would now be
9 8 7 6 5 4 3 2 A J 10
Then wave your hand over the cards and silently count 7 cards over from left to right. Turn the 7th card over. It's the three!!!
It doesn't matter how many cards they move over, this will always work.
Always count 7 cards over (starting with the setup above) and it'll be the number of cards they moved.
If they decide not to move any at all the card will be a Joker and this tells you they didn't move any at all.