Mathematical magic tricks for kids

My six-year-old son loves the website ActivityTV.com, especially their science, origami, cooking, and magic videos. I watched a few of the magic how-to videos with him and was pleasantly surprised to see that some of them had a distinctly mathematical feel to them. For example: Jumping rubber bands: topological properties of circles and linked circles…

A card trick that will probably amaze your friends (solution)

Warning! Spoiler alert! This post contains the secret behind the card trick that I described in my last post. Read that post before reading this one. First the bad news: this card trick is not fool-proof; it is a probabilistic card trick. The good news is that in my experience, it has a high probability…

A card trick that will probably amaze your friends

Here’s a neat card trick that I learned a few years ago. I can’t remember where I read about it. If anyone knows the source of trick, please post it in the comments. [Update: I now know more about the origin of this trick. I’ll write more in my follow-up post.] Thoroughly shuffle an ordinary…

Kindergarten Mathematics (part 2): a report

Last week I wrote a blog post asking for suggestions for math to present to my son’s kindergarten class. My readers posted many great comments. Thank you all. Today was the big day,… and it was a great success! I began by talking about what I do. My son introduced me as a math teacher….