As with multiples and factors, the children should already be familiar with prime numbers from P6. Complete the BBC Bitesize activity and watch the Corbettmaths video. They could also watch around the first eight minutes of the BBC Bitesize programme but they don't have to. They should then work through the different activities. To identify the prime numbers on the first activity, they should use a 'sieving' method: cross out 1 as 1 isn't considered to be a prime number; shade/colour all the multiples of 2 apart from 2; shade/colour all the multiples of 3 still left apart from 3; shade/colour any multiples of 5 still left apart from 5 and, finally, shade/colour any multiples of 7 still left apart from 7 (watch for a couple in the 90s!) If this is done correctly, all the unshaded/uncoloured numbers are prime numbers.