A game in which players take it in turns to choose a number. Can you block your opponent?

Can you make square numbers by adding two prime numbers together?

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

What happens if you join every second point on this circle? How about every third point? Try with different steps and see if you can predict what will happen.

Factors and Multiples game for an adult and child. How can you make sure you win this game?

Use cubes to continue making the numbers from 7 to 20. Are they sticks, rectangles or squares?

Take the number 6 469 693 230 and divide it by the first ten prime numbers and you'll find the most beautiful, most magic of all numbers. What is it?

This problem is based on a code using two different prime numbers less than 10. You'll need to multiply them together and shift the alphabet forwards by the result. Can you decipher the code?

Using all ten cards from 0 to 9, rearrange them to make five prime numbers. Can you find any other ways of doing it?

Work out Tom's number from the answers he gives his friend. He will only answer 'yes' or 'no'.

Use this grid to shade the numbers in the way described. Which numbers do you have left? Do you know what they are called?

These two group activities use mathematical reasoning - one is numerical, one geometric.