Can you work out what a ziffle is on the planet Zargon?

On the planet Vuv there are two sorts of creatures. The Zios have 3 legs and the Zepts have 7 legs. The great planetary explorer Nico counted 52 legs. How many Zios and how many Zepts were there?

48 is called an abundant number because it is less than the sum of its factors (without itself). Can you find some more abundant numbers?

Find at least one way to put in some operation signs (+ - x รท) to make these digits come to 100.

Use 4 four times with simple operations so that you get the answer 12. Can you make 15, 16 and 17 too?

Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.

Which is quicker, counting up to 30 in ones or counting up to 300 in tens? Why?

Explore Alex's number plumber. What questions would you like to ask? Don't forget to keep visiting NRICH projects site for the latest developments and questions.

This article explores the use of the array to support children's thinking around multiplication and division.