How big is the bird?

A deceptive brain teaser about profit sharing.

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

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

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

Here's one of our favourite strategy games.

Stretch your mind with this mess-free egg puzzle.

A logic teaser in honour of George Boole.

Exploring the five different notions of average.

Making a biased coin fair.

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

Making a very special number out of primes.

A life insurance agent knocks on a door and deals with an awkward customer.

Find the number x that satisfies two interesting properties.

A mad robot sets off on a journey mindlessly following a set of instructions. Where will it explode?

Sharpen that wooden stake!

Which gives a tighter fit?

How many prisoners escape after visits from wardens?

Which very famous mathematician's birthday has this property?

Can you make 2011 out of 4s?

What were the scores in each match if these are the league tables?

How many pieces can you make out of a cube of cheese using a cheese wire?

If you think you know how to use the numbers 1 to 9, then try our challenge!

Explore different types of averages in this puzzle.