#MathProblemOfTheDay: Halloween Costume Puzzle


Remains of my last minute Halloween costume.

I dressed up as a puzzle. I taped numbers all over my pants. They were sorted into 2 clumps: one clump on each leg.  All the numbers on my left leg had something in common, and all the numbers on my right leg had something in common.

Hint: none of these numbers is divisible by 3.

Can you figure out why the numbers are sorted this way?

Math and the Colbert Report

This is fun. Terence Tao is a famous mathematician who won a Fields medal in 2006. He talks with Stephen Colbert about prime numbers and why mathematicians care about them.


I like when he says, “we know at least one of these things is infinite, ’cause when we add them all together, we get infinity.”

It’s similar reasoning to something you’ve probably done in your high school algebra class: if three things, when multiplied together, come out to zero, then at least one of them has to be equal to zero.

In other words, if you have mystery quantities A, B, and C, and you know

A*B*C = 0,

then at least one of them (A, B, and/or C) must be zero.

Terence Tao is saying that if you have mystery quantities A, B and C, and you know

A + B + C = infinity,

then at least one of them (A, B, and/or C) must be infinite.

Cool to see the same type of logic that we apply to a basic algebra problem, being used at the forefront of mathematical research!

Another fun moment is when Tao is giving examples of twin primes: “5 and 7, 11 and 13, 27 and uh……”

Is 27 prime??

Even the experts make mistakes 🙂