Cross-Check

## For Pi Day: A Reminiscence on “The Death of Proof”*

In 1993, when I was a full-time staff writer for Scientific American, my boss, Jonathan Piel, asked, or rather, commanded me to write an in-depth feature on something, anything, mathematical. Fercrissake, I was an English major! I whined. I could fake math knowledge for little news stories about the Mandelbrot set or Fermat’s last theorem, [...]

Guest Blog

## How Many Digits of Pi Do You Really Need to Know? Find Out with This Bar Bet

A physicist or engineer who uses π (pi) in numerical calculations may need to have access to 5 or 15 decimal place approximations to this special number, but most of us—mathematicians included—don’t need to know more (decimal-wise) than the fact that it’s roughly 3.14. Yet there is an inexplicable nerdy subculture far removed from real [...]

Observations

## American Pi: Why the Day Belongs to the U.S. (and Belize)

Pi may be a universal constant, but only two countries can natively celebrate Pi Day: the U.S. and Belize. That’s because they are the only ones (if Wikipedia is correct) to shorthand their date format so that it can match the first few digits of pi (3.1415), or March 14, 2015. Most of the rest [...]

Observations

## Glow Sticks Prove the Math Theorem behind the Famous Flatiron Building

How many math lovers live in New York City? It’s a tough count to make, but the Museum of Mathematics made progress at its first anniversary celebration on Thursday, December 5. With a mission to illuminate the math that permeates our day-to-day lives, the Museum of Mathematics, or MoMath, wasn’t about to waste its birthday [...]

Roots of Unity

## What’s so Great about Continued Fractions?

The more I learn about continued fractions, the more enamored I am with them. Last week, when I wrote about how much better continued fractions are than the arbitrary decimal digits we usually use to describe numbers, I mentioned that continued fractions tell us the “best approximations” of irrational numbers. Continued fractions are just fractions [...]

Roots of Unity

## Don’t Recite Digits to Celebrate Pi. Recite Its Continued Fraction Instead.

The digits of pi reciting contest is an all-too-common Pi Day event. And as this year is a once-in-a-century confluence of month/day/year with the first few decimal digits of pi, we might be in for more of those than usual. Our 10 fingers make decimal digits a natural choice, but if we were capybaras or [...]

Roots of Unity

## A Different Pi for Pi Day

The symbol π is overloaded in math: depending on context and capitalization, π could be the constant we all know and love (or hate), a projection, a product, or a function. There’s plenty of stuff to read about the circle constant, so today I’m writing about one of those other π’s. Today’s π is the [...]

Roots of Unity

## The Top n Math Videos Involving Food

It’s food week here on the Scientific American blog network. Food is a really important part of our health, and there’s a lot to learn about the science of food: taste, health, agriculture, how we eat. You could be reading enlightening, important articles about GMO labeling and antibiotic use in farming, or the first posts [...]

Roots of Unity

## How Much Pi Do You Need?

I am traveling for most of July. I hope you enjoy this post from the past, which originally appeared on the Observations blog on July 21, 2012. I hope you’re ready for your big Pi Approximation Day party! You might have observed Pi Day on March 14. It gets its name from 3.14, the first three [...]

Roots of Unity

## Big Numbers Are Big

Today I have a piece in Slate about that pi meme that’s been going around. According to the meme, your life story is encoded in pi somewhere. My life story would probably include the word “Evelyn” at some point. (I’m going out on a limb, but stay with me.) In a code that assigns the [...]

Roots of Unity

## I’m Not Celebrating Pi Day This Year

On the one hand, I like Pi Day because I get to eat pizza and/or pie, and I like things that get people excited about math, but on the other hand, I’m an adult, and I get to eat pizza and/or pie whenever I want, Pi Day or no. Like Matt at Math Goes Pop, [...]