Watch the video below:
If you can't access YouTube, here is a direct link to the video: TruthOrLie.mp4. You can view closed captions by selecting 'CC' in the bottom menu of the video once it is playing.
What do you notice?
Do you have any questions?
Watch it again.
Perhaps some of your questions have been answered. Or you might have thought of new questions.
Using a pack of cards, can you work out how to perform the trick yourself?
Why is this maths and not magic?
This trick, sometimes called The Nine Card Problem, was invented by Jim Steinmeyer.