A Klein bottle can't hold any liquid because it doesn't have an inside. How do you construct this strange thing and why would you want to?
What is 1-1+1-1+1-1+...? How infinite sums challenge our notion of arithmetic.
How to write a sum that's infinitely long.
Here's an easy game that leads you straight to an unsolved question in maths.
How to write down unimaginably large numbers using just a few symbols.
A little trig helps to find the relative distance to the Sun and Moon.