Exploring and noticing

$Countdown fractions$

problem
Countdown fractions

Age

11 to 16

Challenge level

Here is a chance to play a fractions version of the classic Countdown Game.
problem
Triangle in a trapezium

Age

11 to 16

Challenge level

Can you find and prove the relationship between the area of a trapezium and the area of a triangle constructed within it?
problem
Charitable pennies

Age

7 to 14

Challenge level

Investigate the different ways that fifteen schools could have given money in a charity fundraiser.
problem
Standard index form matching

Age

14 to 16

Challenge level

Can you match these calculations in Standard Index Form with their answers?
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?