Many numbers can be expressed as the sum of two or more consecutive integers. For example, 15=7+8 and 10=1+2+3+4. Can you say which numbers can be expressed in this way?

Many numbers can be expressed as the difference of two perfect squares. What do you notice about the numbers you CANNOT make?

In a three-dimensional version of noughts and crosses, how many winning lines can you make?

Charlie likes tablecloths that use as many colours as possible, but insists that his tablecloths have some symmetry. Can you work out how many colours he needs for different tablecloth designs?

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?

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

Caroline and James pick sets of five numbers. Charlie chooses three of them that add together to make a multiple of three. Can they stop him?

Weekly Problem 44 - 2011

You have already used Magic Squares, now meet an Anti-Magic Square. Its properties are slightly different, but can you still solve it...

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

It's easy to work out the areas of most squares that we meet, but what if they were tilted?

Imagine a large cube made from small red cubes being dropped into a pot of yellow paint. How many of the small cubes will have yellow paint on their faces?

Weekly Problem 30 - 2012

Can you work out the number of chairs at a cafe from the number of legs?

Can you find the values at the vertices when you know the values on the edges?

Weekly Problem 24 - 2013

What is the maximum number of T shaped pieces that can be placed on the grid without overlapping?

Weekly Problem 26 - 2013

Is it possible to arrange the numbers 1-6 on the nodes of this diagram, so that all the sums between numbers on adjacent nodes are different?

Weekly Problem 50 - 2013

Each letter in this sum represents a different digit. How many solutions are there?

Is this a fair game? How many ways are there of creating a fair game by adding odd and even numbers?

Weekly problem 48 - 2006

The 30 students in a class have 25 different birthdays between them. What is the largest number that can share any birthday?

Weekly Problem 6 - 2007

Who is the youngest in this family?

Weekly Problem 20 - 2007

In this addition each letter stands for a different digit, with S standing for 3. What is the value of YxO?

Can you describe this route to infinity? Where will the arrows take you next?

Weekly Problem 41 - 2007

The Queen of Spades always lies for the whole day or tells the truth for the whole day. Which of these statements can she never say?

Weekly Problem 51 - 2008

This grid can be filled up using only the numbers 1, 2, 3, 4, 5 so that each number appears just once in each row, once in each column and once in each diagonal. Which number goes in the centre square?

Weekly Problem 29 - 2009

Fill in the grid with A-E like a normal Su Doku. Which letter is in the starred square?

In this problem, we have created a pattern from smaller and smaller squares. If we carried on the pattern forever, what proportion of the image would be coloured blue?

Weekly Problem 7 - 2010

Using the hcf and lcf of the numerators, can you deduce which of these fractions are square numbers?

Weekly Problem 35 - 2010

Knights always tell the truth. Knaves always lie. Can you catch these knights and knaves out?

Weekly Problem 27 - 2011

Pizza, Indian or Chinese takeaway. Each teenager from a class only likes two of these, but can you work which two?

Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make?

Charlie has made a Magic V. Can you use his example to make some more? And how about Magic Ls, Ns and Ws?

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

Weekly Problem 47 - 2014

Which digit replaces x in this crossnumber?

Weekly Problem 11 - 2015

If it takes 852 digits to number all the pages of a book, what is the number of the last page?

Weekly Problem 13 - 2015

When the numbers from 1 to 1000 are written on a blackboard, which digit appears the most number of times?

Weekly Problem 14 - 2015

The digits 1-9 have been written in the squares so that each row and column sums to 13. What is the value of n?

Weekly Problem 20 - 2015

Four brothers give statements about the order they were born in. Can you work out which two are telling the truth?

Weekly Problem 30 - 2015

How many ways are there of completing this table so that each row tells you how many there are of the numbers 1, 2, 3 and 4?

Weekly Problem 32 - 2015

Can you work out the missing numbers in this multiplication magic square?

Weekly Problem 50 - 2015

Can you work out the values of J, M and C in this sum?

Weekly Problem 8 - 2016

The diagram shows a quadrilateral $ABCD$, in which $AD=BC$, $\angle CAD=50^\circ$, $\angle ACD=65^\circ$ and $\angle ACB=70^\circ$. What is the size of $\angle ABC$?

Weekly Problem 39 - 2016

In the diagram, VWX and XYZ are congruent equilateral triangles. What is the size of angle VWY?

Weekly Problem 41 - 2016

The diagram shows a square, with lines drawn from its centre. What is the shaded area?

Weekly Problem 22 - 2017

Peter wrote a list of all the numbers that can be formed by changing one digit of the number 200. How many of Peter's numbers are prime?

Weekly Problem 3 - 2017

Books cost £3.40 and magazines cost £1.60. If Clara spends £23 on books and Magazines, how many of each does she buy?

Weekly Problem 38 - 2017

In the diagram, what is the value of $x$?

Weekly Problem 47 - 2017

How many numbers do I need in a list to have two squares, two primes and two cubes?