This article for the young and old talks about the origins of our number system and the important role zero has to play in it.
Investigate the different ways these aliens count in this challenge. You could start by thinking about how each of them would write our number 7.
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.
How would you count the number of fingers in these pictures?
Here are many ideas for you to investigate - all linked with the number 2000.
A collection of games on the NIM theme