Mind Your Decisions

New Video – Divisibility By 11 Rule

In school you may have learned several divisibility rules 2 (last digit is even) 3 (sum is a multiple of 3) 5 (last digit is 0 or 5) 6 (divisible by 2 and 3) 9 (sum is a multiple of 9) In…

- 3 weeks, 3 days, 3 hours, 3 minutes ago

How Many Times Do You Need To Shuffle A Deck Of Cards? [Numberphile Video]

There’s a great video posted by Numberphile on YouTube. The topic is how many shuffles it takes to make a deck truly random, featuring Persi Diaconis who’s a math/stats prof at…

- 3 weeks, 4 days, 20 hours, 11 minutes ago

A New Scientist Video Almost Messes Up The Monty Hall Problem (Ultimately Gets It Right)

There are some great educational and entertaining videos on the NewScientist YouTube channel. Recently I was excited to see a video about how probability can save your life. But there was a…

- 3 weeks, 5 days, 20 hours, 50 minutes ago

The Hardest Multiple Choice Question Ever – Sunday Puzzle

If you choose an answer to this question at random, what is the chance you will be correct? A) 25% B) 50% C) 0% D) 25% Give it a few moments before reading my thoughts. . . . . M I N D . Y…

- 1 month, 4 hours, 22 minutes ago

Double Dealing Math Card Trick (Video) And Why It Works

I’ve posted a new video on YouTube about a cool mathematical card trick. Video – Double Dealing Math Card Trick I summarize the card trick and why it works after the jump. …

- 1 month, 2 days, 20 hours, 25 minutes ago

Game Theory Tips For Your NCAA Bracket Challenge

The college men’s basketball tournament is about to start. What’s the best strategy to win a bracket challenge? This post considers maximizing your expected payout from winning,…

- 1 month, 6 days, 3 hours, 34 minutes ago

Site Redesign

Last week I completely redesigned the site so it’s easier to view on tablets and smartphones, as more traffic is coming from mobile devices. Mostly it’s the look of the site…

- 1 month, 6 days, 21 hours, 58 minutes ago

Monday Puzzle NCAA Tournament Edition. What are the odds of picking a perfect bracket? Should you enter more than 1 bracket?

image by Marianne O’Leary. CC BY 2.0 The college men’s basketball tournament is about to start, so this week’s puzzle is about the mathematics of tournaments. I have asked…

- 1 month, 1 week, 2 hours, 48 minutes ago

Solution To The Marble Color Puzzle

Last week I posed the Marble Color Puzzle. This problem is known as the Bertrand Box Paradox and in included in my book 40 Paradoxes in Logic, Probability, and Game Theory. (5 stars on…

- 1 month, 1 week, 2 hours, 50 minutes ago

5 Facts You Should Know About Pi (Happy Pi Day!)

Happy Pi Day! At 3/14/15 when the time is 9:26, am and pm, the time will be accurate to pi for 7 decimal places. What’s your favorite fact about pi? I made a video with 5 facts for…

- 1 month, 1 week, 2 days, 4 hours, 25 minutes ago