Take a look at the interactive below. 

What do you notice?
What do you wonder?

This kind of table is called a Carroll diagram (named after the mathematician and author Lewis Carroll). 

Can you drag the numbers into their correct places?
How do you know where to put them?

If you would prefer to work away from a computer, you could print off this sheet.

How about this Carroll diagram? The interactivity is below, or you could print off this sheet.

You may like to print off this sheet, which is a picture of a completed Carroll diagram, but the labels are missing. Can you give the rows and columns labels by choosing from the list at the side?

If you click on the purple cog of the interactivity, you can change the settings and create your own Carroll diagrams for someone else to complete.