Addition and subtraction

problem

Painting Possibilities

Age

7 to 11

Challenge level

This task, written for the National Young Mathematicians' Award 2016, involves open-topped boxes made with interlocking cubes. Explore the number of units of paint that are needed to cover the boxes and the small cubes that would fit inside each one.
problem

Open Squares

Age

7 to 11

Challenge level

This task, written for the National Young Mathematicians' Award 2016, focuses on 'open squares'. What would the next five open squares look like?
problem

Sometimes We Lose Things

Age

7 to 11

Challenge level

Well now, what would happen if we lost all the nines in our number system? Have a go at writing the numbers out in this way and have a look at the multiplications table.
problem

On Target

Age

7 to 11

Challenge level

You have 5 darts and your target score is 44. How many different ways could you score 44?
problem

Let's Face It

Age

7 to 11

Challenge level

In this problem you have to place four by four magic squares on the faces of a cube so that along each edge of the cube the numbers match.
problem

The 24 Game

Age

7 to 11

Challenge level

There are over sixty different ways of making 24 by adding, subtracting, multiplying and dividing all four numbers 4, 6, 6 and 8 (using each number only once). How many can you find?
problem

Sam's Quick Sum

Age

7 to 11

Challenge level

What is the sum of all the three digit whole numbers?
problem

Oddly

Age

7 to 11

Challenge level

Find the sum of all three-digit numbers each of whose digits is odd.
problem

Difference

Age

7 to 11

Challenge level

Place the numbers 1 to 10 in the circles so that each number is the difference between the two numbers just below it.
problem

Pouring the Punch Drink

Age

7 to 11

Challenge level

There are 4 jugs which hold 9 litres, 7 litres, 4 litres and 2 litres. Find a way to pour 9 litres of drink from one jug to another until you are left with exactly 3 litres in three of the jugs.