Anna, Ben and Charlie have been estimating 30 seconds. Who is the best?

Construct a line parallel to one side of a triangle so that the triangle is divided into two equal areas.

Can you locate the point on an annulus that splits it into two areas?

Two of the four small triangles are to be painted black. In how many ways can this be done?

The horizontal red line divides this equilateral triangle into two shapes of equal area. How long is the red line?

Weekly Problem 21 - 2009

What is the angle between the two hands of a clock at 2.30?

What could the half time scores have been in these Olympic hockey matches?

Can you find a number that is halfway between two fractions?

One year there were exactly four Tuesdays and four Fridays in October. On what day of the week was Halloween.

Ana and Ross looked in a trunk in the attic. They found old cloaks and gowns, hats and masks. How many possible costumes could they make?

What are the possible dimensions of a rectangular hallway if the number of tiles around the perimeter is exactly half the total number of tiles?

These pictures show squares split into halves. Can you find other ways?

Draw any triangle PQR. Find points A, B and C, one on each side of the triangle, such that the area of triangle ABC is a given fraction of the area of triangle PQR.

I start my journey in Rio de Janeiro and visit all the cities as Hamilton described, passing through Canberra before Madrid, and then returning to Rio. What route could I have taken?

Weekly Problem 36 - 2007

Find the length along the shortest path passing through certain points on the cube.

Resources to accompany Charlie's workshops and presentation.

Use your hand span to measure the distance around a tree trunk. If you ask a friend to try the same thing, how do the answers compare?

My train left London between 6 a.m. and 7 a.m. and arrived in Paris between 9 a.m. and 10 a.m. At the start and end of the journey the hands on my watch were in exactly the same positions but the. . . .

This collection of activities covers the areas of probability and collecting and analysing data.

This collection of resources is designed to help students to improve their understanding of topics in Handling Data.

This collection of resources is designed to help you to improve your understanding of topics in Handling Data.

These challenges will test your understanding of information, as well as how likely different events are.

These challenges will test your understanding of different types of information.

A collection of short Stage 3 and 4 problems on handling data.

These KS1 tasks introduce the skills of collecting data systematically and using it to answer questions.

These KS2 tasks build on the skills of systematically collecting and interpreting data.

Sometime during every hour the minute hand lies directly above the hour hand. At what time between 4 and 5 o'clock does this happen?

Can you find an efficient method to work out how many handshakes there would be if hundreds of people met?

Weekly Problem 39 - 2008

How big is the angle between the hour hand and the minute hand of a clock at twenty to five?

To celebrate NRICH's 20th birthday, we have brought together some tasks from NRICH which you might not have come across before. We might call them 'hidden gems'!

To celebrate NRICH's 20th birthday, we have brought together some tasks from NRICH which you might not have come across before. We might call them 'hidden gems'!

Can you split each of the shapes below in half so that the two parts are exactly the same?

This investigation is about happy numbers in the World of the Octopus where all numbers are written in base 8 ... Find all the fixed points and cycles for the happy number sequences in base 8.

Can you interpret this algorithm to determine the day on which you were born?

Find out about the five-term project (January 2014 to July 2015) which NRICH is leading in conjunction with Haringey Council, funded by London Schools Excellence Fund.

Find out about the primary maths Leadership project that NRICH is running in Haringey during the academic year 2015-16.

Can you see how to build a harmonic triangle? Can you work out the next two rows?

Is it true that a large integer m can be taken such that: 1 + 1/2 + 1/3 + ... +1/m > 100 ?

Can you explain the strategy for winning this game with any target?

What fraction of the larger circle is outside the smaller circle?