Exploring and noticing

problem
Terminating or not

Age

11 to 14

Challenge level

Is there a quick way to work out whether a fraction terminates or recurs when you write it as a decimal?
problem
Digit addition

Age

5 to 11

Challenge level

Try out this number trick. What happens with different starting numbers? What do you notice?
problem
The Number Jumbler

Age

7 to 14

Challenge level

The Number Jumbler can always work out your chosen symbol. Can you work out how?
problem
Sticky dice

Age

7 to 11

Challenge level

Throughout these challenges, the touching faces of any adjacent dice must have the same number. Can you find a way of making the total on the top come to each number from 11 to 18 inclusive?
problem
Different deductions

Age

7 to 11

Challenge level

There are lots of different methods to find out what the shapes are worth - how many can you find?
problem
Name that triangle!

Age

7 to 11

Challenge level

Can you sketch triangles that fit in the cells in this grid? Which ones are impossible? How do you know?
problem
Magic crosses

Age

7 to 14

Challenge level

Can you find examples of magic crosses? Can you find all the possibilities?
problem
Polygon rings

Age

11 to 14

Challenge level

Join pentagons together edge to edge. Will they form a ring?
problem
Bundles of cubes

Age

7 to 11

Challenge level

Watch this animation. What do you notice? What happens when you try more or fewer cubes in a bundle?
problem
Oldest and youngest

Age

14 to 16

Challenge level

Edith had 9 children at 15 month intervals. If the oldest is now six times as old as the youngest, how old is her youngest child?