unit fraction

The number 1 can be written as a sum of unit fractions, that is fractions with 1 in the numerator. But how long can we make such a sum?

Maths in a minute

Want facts and want them fast? Our Maths in a minute series explores key mathematical concepts in just a few words.

Maths in a minute: The axioms of probability theory

Take a quick trip to the foundations of probability theory.
Arithmetic billiards

Need to find the least common multiple or greatest common divisor of two numbers? A billiard table of the right proportions holds the answers!
Clocking the schedule

The way many football leagues schedule their fixtures can lead to unfair effects — and unsolved maths problems!
The real numbers and Cauchy sequences

We take the real numbers for granted, but what are they really?
Citizen science: Schumann resonances

Resonant electromagnetic waves, created by lightning flashes, circle the Earth. Wim Hordijk explores the maths and shows how you can keep track with these phenomena.