Prime numbers

problem
Xavi's T-shirt

Age

7 to 16

Challenge level

How much can you read into a T-shirt?
problem
Factors and multiples puzzle

Age

11 to 14

Challenge level

Using your knowledge of the properties of numbers, can you fill all the squares on the board?
problem
Flow chart

Age

11 to 14

Challenge level

The flow chart requires two numbers, M and N. Select several values for M and try to establish what the flow chart does.
problem
How much can we spend?

Age

11 to 14

Challenge level

A country has decided to have just two different coins. Which totals can be made? Is there a largest total that cannot be made? How do you know?
problem
Sieve of Eratosthenes

Age

11 to 14

Challenge level

Follow this recipe for sieving numbers and see what interesting patterns emerge.
problem
Stars

Age

11 to 14

Challenge level

Can you work out what step size to take to ensure you visit all the dots on the circle?
problem
Coins

Age

11 to 14

Challenge level

A man has 5 coins in his pocket. Given the clues, can you work out what the coins are?
problem
Different by one

Age

14 to 16

Challenge level

Can you make lines of Cuisenaire rods that differ by 1?
problem
Why 24?

Age

14 to 16

Challenge level

Take any prime number greater than 3 , square it and subtract one. Working on the building blocks will help you to explain what is special about your results.
problem
Prime sequences

Age

16 to 18

Challenge level

This group tasks allows you to search for arithmetic progressions in the prime numbers. How many of the challenges will you discover for yourself?