Get smart curated videos delivered to your inbox.   SUBSCRIBE
The Kid Should See This

Mental Logs number sticks, a math magic trick

Ask someone to mix these Mental Logs number sticks up in any combination. Can you figure out the total in your head more quickly than they can add the numbers on a calculator? Yes. In fact, you can probably tell them the total faster than it takes them to enter the first number. How does this math magic trick work?

Mathematician Dr. Katie Steckles demonstrates a simple mental math trick in this Numberphile video: Number Sticks. Buy the Mental Logs magic trick on Amazon, or make your own. How long can you confound your friends, family, and classroom before they figure out how it works?

Follow this with the Universal Calendar Puzzle: Figure out the day of the week for any date ever and how to multiply numbers by drawing lines.

Previously: Fold & Cut Theorem – Cut any shape from only one cut.

This Webby award-winning video collection exists to help teachers, librarians, and families spark kid wonder and curiosity. TKSST features smarter, more meaningful content than what's usually served up by YouTube's algorithms, and amplifies the creators who make that content.

Curated, kid-friendly, independently-published. Support this mission by becoming a sustaining member today.

The makers of the SAVE plug-in are no longer supporting it. For site speed and security, I've chosen to discontinue its use. If you have saved videos, please back them up with browser bookmarks, Pinterest, or another page saving tool, before they disappear in May 2021. Thank you.
This video was posted 2 years ago.

Watch more videos about...