During the third hour after midnight the hands on a clock point in
the same direction (so one hand is over the top of the other). At
what time, to the nearest second, does this happen?
Alice's mum needs to go to each child's house just once and then
back home again. How many different routes are there? Use the
information to find out how long each road is on the route she
On a digital clock showing 24 hour time, over a whole day, how many
times does a 5 appear? Is it the same number for a 12 hour clock
over a whole day?
Stuart's watch loses two minutes every hour. Adam's watch gains one
minute every hour. Use the information to work out what time (the
real time) they arrived at the airport.
Draw some isosceles triangles with an area of $9$cm$^2$ and a vertex at (20,20). If all the vertices must have whole number coordinates, how many is it possible to draw?
Can you help the children find the two triangles which have the
lengths of two sides numerically equal to their areas?
If you have only 40 metres of fencing available, what is the maximum area of land you can fence off?
Many natural systems appear to be in equilibrium until suddenly a critical point is reached, setting up a mudslide or an avalanche or an earthquake. In this project, students will use a simple. . . .
The challenge here is to find as many routes as you can for a fence
to go so that this town is divided up into two halves, each with 8
How have "Warmsnug" arrived at the prices shown on their windows? Which window has been given an incorrect price?
This practical challenge invites you to investigate the different
squares you can make on a square geoboard or pegboard.
These rectangles have been torn. How many squares did each one have
inside it before it was ripped?
Can you draw a square in which the perimeter is numerically equal
to the area?
Investigate all the different squares you can make on this 5 by 5
grid by making your starting side go from the bottom left hand
point. Can you find out the areas of all these squares?
Use the interactivity to find all the different right-angled
triangles you can make by just moving one corner of the starting
A thoughtful shepherd used bales of straw to protect the area
around his lambs. Explore how you can arrange the bales.
What can you say about these shapes? This problem challenges you to
create shapes with different areas and perimeters.
You cannot choose a selection of ice cream flavours that includes
totally what someone has already chosen. Have a go and find all the
different ways in which seven children can have ice cream.
My cousin was 24 years old on Friday April 5th in 1974. On what day
of the week was she born?
The pages of my calendar have got mixed up. Can you sort them out?
Can you order pictures of the development of a frog from frogspawn
and of a bean seed growing into a plant?
When newspaper pages get separated at home we have to try to sort
them out and get things in the correct order. How many ways can we
arrange these pages so that the numbering may be different?
Cut differently-sized square corners from a square piece of paper
to make boxes without lids. Do they all have the same volume?
If we had 16 light bars which digital numbers could we make? How
will you know you've found them all?
In this game for two players, you throw two dice and find the product. How many shapes can you draw on the grid which have that area or perimeter?
On a digital 24 hour clock, at certain times, all the digits are
consecutive. How many times like this are there between midnight
and 7 a.m.?
What is the smallest number of tiles needed to tile this patio? Can
you investigate patios of different sizes?
What is the date in February 2002 where the 8 digits are
palindromic if the date is written in the British way?
If you have three circular objects, you could arrange them so that
they are separate, touching, overlapping or inside each other. Can
you investigate all the different possibilities?
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
What is the largest 'ribbon square' you can make? And the smallest? How many different squares can you make altogether?
My local DIY shop calculates the price of its windows according to the area of glass and the length of frame used. Can you work out how they arrived at these prices?
An investigation that gives you the opportunity to make and justify
These practical challenges are all about making a 'tray' and covering it with paper.
How many ways can you find of tiling the square patio, using square
tiles of different sizes?
In this matching game, you have to decide how long different events take.
Here you see the front and back views of a dodecahedron. Each
vertex has been numbered so that the numbers around each pentagonal
face add up to 65. Can you find all the missing numbers?
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?
Four numbers on an intersection that need to be placed in the
surrounding cells. That is all you need to know to solve this
A Sudoku with a twist.
There were chews for 2p, mini eggs for 3p, Chocko bars for 5p and
lollypops for 7p in the sweet shop. What could each of the children
buy with their money?
How many shapes can you build from three red and two green cubes? Can you use what you've found out to predict the number for four red and two green?
Four small numbers give the clue to the contents of the four
Ben passed a third of his counters to Jack, Jack passed a quarter
of his counters to Emma and Emma passed a fifth of her counters to
Ben. After this they all had the same number of counters.
A Sudoku with clues as ratios.
Are all the possible combinations of two shapes included in this
set of 27 cards? How do you know?
Find out what a "fault-free" rectangle is and try to make some of
Use the differences to find the solution to this Sudoku.
Can you coach your rowing eight to win?
This package contains a collection of problems from the NRICH
website that could be suitable for students who have a good
understanding of Factors and Multiples and who feel ready to take
on some. . . .