## Mathematicians’ Phone Passcodes

A character in a novel I was reading used the passcode 1729 for his house’s security system. He did so because of the famous Hardy-Ramanujan anecdote about the number. That got me to thinking. What would mathematicians of the past have used for their passcodes? I tweeted some ideas and got some great responses with…

## How to Present a Mathematical Proof or Problem

There are many useful websites containing advice on how to give a good mathematics presentation (such as those listed here). But these are written for scholars who are giving lectures on their research. They focus on organizing the talk, putting the research in context, deciding what to include or not include, designing slides, pacing and…

## Tales of Impossibility: Now Published!

I’m very excited to announce that my new book, Tales of Impossibility: The 2000-Year Quest to Solve the Mathematical Problems of Antiquity (Princeton University Press, 2019), is now available! (OK. It was published about a month ago, but I am just now getting around to blogging about it.) Like my previous book, Euler’s Gem (Princeton University…

## Make Your Own Pythagorean Cup

My parents recently went to Greece. They brought me back a souvenir—a practical joke cup called a “Pythagorean cup.” The legend behind the cup is that Pythagoras or one of the Pythagoreans invented this cup to prevent gluttony. The vessel looks like a cup with an odd pillar in the center. When you fill it…

## Card Table Proof of the Pythagorean Theorem

We own a standard card table that we leave tucked away in the basement until the kids want to have a lemonade stand on the front sidewalk or we need the extra table space for a large Thanksgiving dinner. It is the standard kind with legs that fold underneath it so it is easy to store….

## Editing mathematical writing

As I mentioned in a previous post, I’ve been assigning large-scale collaborative writing projects in my mathematics classes. I’ve had my topology students write a textbook for their class, and this semester I’ve been doing the same in my discrete mathematics class. As I mentioned in that post, the approach has been very successful, but…

## Mathematics in Moby-Dick

Twice before I have posted mathematical passages that I have stumbled upon in works of literature. Yesterday I finished reading Moby-Dick (great book, great ending!), so I thought I’d highlight a few mathematical passages that it contains. Especially interesting to me is the second one in which Melville mentions the impossibility of squaring a circle….

## Catching up on some reading: Dyson’s birds and frogs

The semester’s over and I’ve been cleaning off my desk. I found an old issue of the Notices of the AMS (February 2009) with a bookmark in it. It was Freeman Dyson‘s Einstein Lecture entitled “Birds and Frogs.” Here are some good quotes from it. He opens with: Some mathematicians are birds, others are frogs….

## Mathematics in novels and Martin Gardner RIP

I always enjoy encountering mathematics in non-mathematical works of fiction. (I posted excerpts from Candide and The Brothers Karamazov last fall.) Here are a few more that I came across recently. The first is in Dashiell Hammett’s 1934 murder mystery The Thin Man. Here is a conversation between private eye Nick Charles and his wife Nora at the…

## Using wikis in mathematics classes

Wikipedia describes a wiki as a website that allows the easy creation and editing of any number of interlinked web pages… [Wikis] are often used to create collaborative websites, to power community websites, for personal note taking, in corporate intranets, and in knowledge management systems. I have used wikis in three of my classes: two…