David Widener

The 21 Card Trick is a ubiquitous card trick seen by millions of people each year. How is it done? Very few people actually know the math and the process behind the trick. Here in this lesson you can perform the trick by handing out a step by step illustration. Students will love this change in math class predictability. After the trick has been performed take a deeper dive into the "why does this trick work every time?" There is a great handout that will be a lesson in patterns and predictabili