How big is the bird?

How big is the bird?

Sharing cakes

A deceptive brain teaser about profit sharing.

Weighing balls

This puzzle is apparently used in job interviews — would you pass?

Magic 19

Number the dots so that each line of three adds up to 22.

Creating squares

Be the first to mark the corners of a square to win this game!


Here's one of our favourite strategy games.

Dropping eggs

Stretch your mind with this mess-free egg puzzle.

Counter logic

A logic teaser in honour of George Boole.

Equal averages

Exploring the five different notions of average.

Crooked coin

Making a biased coin fair.

It's a long way to the top

In how many ways can you make it up the stairs?

Prime mystery

Making a very special number out of primes.