Cafe Math

So, rocks are hard. But the scale we use to rank them, the Mohs scale, is only really good at quantifying that for one kind of hardness, and topaz is a perfect stone to talk about to explain that. And you can check it out in our SciShow Rocks Box subscription!

he number 37 is on your mind more than you think.

Do odd perfect numbers exist?

The most famous equation in finance, the Black-Scholes/Merton equation, came from physics.

There's a strange number system, featured in the work of a dozen Fields Medalists, that helps solve problems that are intractable with real numbers.

A few years ago, the king decided your life would be forfeit unless you tripled the gold coins in his treasury.

Micheal teaches us about the "Odd Number Rule".

You heard the travelers' tales, you followed the maps, and now, you've finally located the dungeon containing a stash of ancient coins. The good news: the wizard who owns the castle has generously agreed to let you have the coins. The bad news: he's not quite as generous about letting you leave the dungeon ... unless you solve his puzzle. Can you solve it and get out alive? Lisa Winer shows how.