A tricky SAT geometry question

Just to show you how hard the SATs were, here’s a question (sent by reader Bryan) that I got wrong. I guessed three, assuming that the circumference of the smaller circle (1/3 of the larger), would translate into rotations needed to get around the circumference of the larger circle. How I got a perfect score […]

Alternative truths: math

Here’s a humorous but not completely unimaginable video about what would happen if elementary schools were taken over by the view that there are “multiple truths”. This attitude already infects some of the social sciences and much of the humanities in universities, but math is not completely immune to the “different ways of knowing” infection. […]

A reasoning puzzle– *the* answer

by Greg Mayer So, here’s the answer given by Manil Suri to the puzzle he posed in the New York Times on Sunday. First, restating the puzzle: Four cards are laid in front of you, each of which, it is explained, has a letter on one side and a number on the other. The sides […]

A reasoning puzzle– an answer

by Greg Mayer Reader Chris G. sent a video of Steve Pinker explaining the very same problem (another reader also mentioned that he had seen a Pinker talk about it). Here it is. I’ll post my own discussion later today. h/t Chris G.

A reasoning puzzle

by Greg Mayer In today’s New York Times, there is an opinion piece by Manil Suri, a mathematician at the University of Maryland, Baltimore County, entitled “Does math make you smarter?” Don’t go and read the piece– that’s why I’ve left out the link! I ask that readers answer the following puzzle he poses in […]

It’s Pi Day!

Having consumed my share of Costco pies the last few weeks (they’re good, too!), I’m happy to report that it’s Pi Day, celebrated with the following Google Doodle (click on screenshot to go to the Doodle site): Google itself explains the Doodle here, adding a video and, at the link, a recipe for a scrumptious […]

Bertrand’s Box paradox: The answer is 2/3!!!

There are almost 200 comments now on my post about Bertrand’s Box Paradox yesterday. Let me reprise the problem and then give the solution the way I hit on it: There are three boxes: a box containing two gold coins, a box containing two silver coins, a box containing one gold coin and a silver […]

Bertrand’s paradox

Reader Peter sent me this paradox (it’s not really a “paradox” as I understand the meaning of that term, but a result that, like the Monty Hall problem, is deeply counterintuitive). It’s called Bertrand’s Box Paradox after French mathematician Joseph Bertrand, who raised it in an 1889 book on probabilities. The setup is simple: There […]

The other social media

by Grania While we are on the subject of social media, GooglePlus is one of the least popular. It’s never really been able to compete with Facebook; despite being moreorless the same, at least in its original intentions. One of the things I like about it is that as a result of its unpopularity there […]

Weird and slightly alarming – the chaos game

by Matthew Cobb This video from the excellent Numberphile YouTube channel shows a very simple game that has the most unexpected outcome. My only criticism of this video is that I’d like to be shown the explanation, even if it’s complicated! Maybe readers can help me.