What are the next three numbers in this sequence? Can you explain why are they called pyramid numbers?

Three circles have a maximum of six intersections with each other. What is the maximum number of intersections that a hundred circles could have?

Polygonal numbers are those that are arranged in shapes as they enlarge. Explore the polygonal numbers drawn here.

While we were sorting some papers we found 3 strange sheets which seemed to come from small books but there were page numbers at the foot of each page. Did the pages come from the same book?

I've made some cubes and some cubes with holes in. This challenge invites you to explore the difference in the number of small cubes I've used. Can you see any patterns?

Can you continue this pattern of triangles and begin to predict how many sticks are used for each new "layer"?

Your challenge is to find the longest way through the network following this rule. You can start and finish anywhere, and with any shape, as long as you follow the correct order.

Make new patterns from simple turning instructions. You can have a go using pencil and paper or with a floor robot.

Let's suppose that you are going to have a magazine which has 16 pages of A5 size. Can you find some different ways to make these pages? Investigate the pattern for each if you number the pages.

"Tell me the next two numbers in each of these seven minor spells", chanted the Mathemagician, "And the great spell will crumble away!" Can you help Anna and David break the spell?

Explore the different tunes you can make with these five gourds. What are the similarities and differences between the two tunes you are given?

Take any two positive numbers. Calculate the arithmetic and geometric means. Repeat the calculations to generate a sequence of arithmetic means and geometric means. Make a note of what happens to the. . . .

Choose a couple of the sequences. Try to picture how to make the next, and the next, and the next... Can you describe your reasoning?

What would you get if you continued this sequence of fraction sums? 1/2 + 2/1 = 2/3 + 3/2 = 3/4 + 4/3 =

How many different ways can I lay 10 paving slabs, each 2 foot by 1 foot, to make a path 2 foot wide and 10 foot long from my back door into my garden, without cutting any of the paving slabs?

Investigate the successive areas of light blue in these diagrams.

Make some loops out of regular hexagons. What rules can you discover?

What is the total area of the first two triangles as a fraction of the original A4 rectangle? What is the total area of the first three triangles as a fraction of the original A4 rectangle? If. . . .

An environment which simulates working with Cuisenaire rods.

Three beads are threaded on a circular wire and are coloured either red or blue. Can you find all four different combinations?

Investigate what happens when you add house numbers along a street in different ways.

If the numbers 5, 7 and 4 go into this function machine, what numbers will come out?

Benâ€™s class were cutting up number tracks. First they cut them into twos and added up the numbers on each piece. What patterns could they see?

Take any whole number between 1 and 999, add the squares of the digits to get a new number. Make some conjectures about what happens in general.

Alison, Bernard and Charlie have been exploring sequences of odd and even numbers, which raise some intriguing questions...

Watch these videos to see how Phoebe, Alice and Luke chose to draw 7 squares. How would they draw 100?

What's the greatest number of sides a polygon on a dotty grid could have?

In this section from a calendar, put a square box around the 1st, 2nd, 8th and 9th. Add all the pairs of numbers. What do you notice about the answers?

What is the remainder when 2^2002 is divided by 7? What happens with different powers of 2?

Square numbers can be represented on the seven-clock (representing these numbers modulo 7). This works like the days of the week.

Choose any 4 whole numbers and take the difference between consecutive numbers, ending with the difference between the first and the last numbers. What happens when you repeat this process over and. . . .

If I use 12 green tiles to represent my lawn, how many different ways could I arrange them? How many border tiles would I need each time?

In this activity, the computer chooses a times table and shifts it. Can you work out the table and the shift each time?

July 1st 2001 was on a Sunday. July 1st 2002 was on a Monday. When did July 1st fall on a Monday again?

Liam's house has a staircase with 12 steps. He can go down the steps one at a time or two at time. In how many different ways can Liam go down the 12 steps?

Here is a machine with four coloured lights. Can you develop a strategy to work out the rules controlling each light?

In this investigation, you are challenged to make mobile phone numbers which are easy to remember. What happens if you make a sequence adding 2 each time?

These sixteen children are standing in four lines of four, one behind the other. They are each holding a card with a number on it. Can you work out the missing numbers?

There are lots of ideas to explore in these sequences of ordered fractions.

How many different sets of numbers with at least four members can you find in the numbers in this box?

Investigate the numbers that come up on a die as you roll it in the direction of north, south, east and west, without going over the path it's already made.

Sissa cleverly asked the King for a reward that sounded quite modest but turned out to be rather large...

There are ten children in Becky's group. Can you find a set of numbers for each of them? Are there any other sets?

Investigate these hexagons drawn from different sized equilateral triangles.

Show that 8778, 10296 and 13530 are three triangular numbers and that they form a Pythagorean triple.