The Third Millennium of Those “Find My Age” Algebra Problems

I’d explain the title of this post, but you already know what I’m talking about. I refer to questions like this one, from the 4th century:

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I, for one, pity old Demochares—enumerating the fractions of his life, yet unable to recall his own age. It’s a bizarre, selective senility, like something from an Oliver Sacks book: “The Man Who Mistook His Life for a Math Problem.”

Or consider this problem, from the 21st century:

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Over the last three millennia, much has changed. Civilizations have risen, collided, and fallen. Revolutions have left legacies in blood and ink. There have been, for good and for ill, 417 million Marvel films. Yet somehow, these age-based math puzzles have remained a constant.

What’s the case for them? Continue reading


The Limitations of Genies (and 18 other math cartoons)

These cartoons first appeared on Facebook and Twitter during the wild and woolly month of January 2018. If you have ever found yourself thinking, “I wish my daily social media experience featured more math puns,” then I encourage you to (A) Follow Math with Bad Drawings! and (B) Take a long, careful look in the mirror to see what you’ve become.

Welcome to 2018

2018.1.1 happy 2018

Some folks on Facebook offered optimistic predictions that the pattern is quadratic, with a negative leading coefficient. This is an adorable sentiment, so please don’t spoil their innocence by disagreeing with them.

Meanwhile, somebody on Twitter suggested sin(x)/x, which is a nice “end of history” prediction. My personal worry is that the world is more like x sin(x).

Continue reading

The ABC Book of e

Roughly speaking, e is 2.718.

More precisely, e is the essence of existence, the fount of human joy, and (for folks who worry that Pi Day is kinda played out) the perfect constant around which to build your mathematical festivities (e-clairs, anyone?).

Get excited, citizens of math, because Wednesday, February 7th, 2018 is e Day: 2/7/18.

(Well… in America, anyway. Our international pals may wait until Monday, July 2nd.)

In honor of this noble number, I offer an alphabetical celebration:

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The Know-Nothing Oscar Pool

You can play here until March 4th!

Backstory: Since 2009, I’ve had an annual Oscars wager with my friend Ryan. From 2009 to 2014, Ryan always won.

Ryan’s advantage? He is much smarter than I am. (Smart friends: I don’t recommend it.) He’d go to and identify the favorite in each category. (For close races, he’d supplement with a little extra research.) While Ryan leveraged the wisdom of the crowds, I’d fall back on my own personal favorites and erratic judgment. I’d lose because I couldn’t keep myself from “clever” (read: stupid) underdog picks.

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Then, in 2015 I devised a new scoring system to neutralize Ryan’s advantage. An Oscar pool for know-nothings like me.

Picks would be scored based on their probability of winning. If prediction markets gave a film a 1-in-2 chance of winning, then its victory was worth 2 points. If they gave it a 1-in-15 chance of winning, then its victory was worth 15 points.

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This system has a simple mathematical property: it equalizes expected value. So you can follow any probabilistic strategy you like. Pick all favorites. Pick all longshots. Pick the nominees whose names make the most appealing anagrams (“Lady Bird” –> “I Dry Bald”; Phantom Thread” –> “Top Hardhat Men”; “The Post” –> “Hot Step”; “Get Out” –> “Toe Tug”).

In the long run, it will all return the same average total: 24 points a year.

Now, it didn’t matter that Ryan is a neurosurgery resident, busy saving lives by mastering the inner workings of the most complex organ in existence. None of that did him any good. What an idiot!

Anyway, this year, I am excited to open up the game to you, with the KNOW-NOTHING OSCAR POOL. Continue reading

The Reluctant Gatekeeper

From time to time, math folks can’t help wrestling with the old, pot-stirring question “Is [algebra/calculus/trigonometry/mathematics] class really necessary?”


The argument goes like this: At every step of education, students face math requirements.


What’s weird is that, once you’ve cleared the bar, you rarely use the math you learned. Continue reading

The Twitter Logo is Just Circles

a roundup post that I wrote in November and never shared,
and now I’ve kinda stopped doing roundup posts,
but hey, here ya go

Suterisms: I recently came across the work of cartoonist David Suter. His images are hard to describe. Artful cartoons? Cartoonish art? Visual puns? More like visual wordplay; “thoughtplay?” It’s what you’d get if you hired MC Escher as a political cartoonist. This one was a favorite of mine:

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Belatedly: RIP, Voevodsky: A tribute to the visionary mathematician Vladimir Voevodsky, who died in 2017.

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