Visualising and representing

Use your skill and knowledge to place various scientific lengths in order of size. Can you judge the length of objects with sizes ranging from 1 Angstrom to 1 million km with no wrong attempts?

If you have a large supply of 3kg and 8kg weights, how many of each would you need for the average (mean) of the weights to be 6kg?

Can you visualise whether these nets fold up into 3D shapes? Watch the videos each time to see if you were correct.

Can you find a reliable strategy for choosing coordinates that will locate the treasure in the minimum number of guesses?

On the graph there are 28 marked points. These points all mark the vertices (corners) of eight hidden squares. Can you find the eight hidden squares?

I am standing behind five pupils who are signalling a five-digit number to someone on the opposite side of the playground. What number is actually being signalled?

Weekly Problem 19 - 2009
When I looked at the greengrocer's window I saw a sign. When I went in and looked from the other side, what did I see?

What 3D shapes occur in nature. How efficiently can you pack these shapes together?

How efficiently can you pack together disks?

How efficiently can various flat shapes be fitted together?