What is the smallest number of answers you need to reveal in order to work out the missing headers?

Try entering different sets of numbers in the number pyramids. How does the total at the top change?

When number pyramids have a sequence on the bottom layer, some interesting patterns emerge...

Can you find the hidden factors which multiply together to produce each quadratic expression?

Join pentagons together edge to edge. Will they form a ring?

In this interactivity each fruit has a hidden value. Can you deduce what each one is worth?

Whenever a monkey has peaches, he always keeps a fraction of them each day, gives the rest away, and then eats one. How long could he make his peaches last for?

There are lots of different methods to find out what the shapes are worth - how many can you find?

What's the largest volume of box you can make from a square of paper?

Can you make sense of information about trees in order to maximise the profits of a forestry company?