## Year 5 Multiplication and division Return to Primary Maths Resources

### Teacher resources.

Sieve of Eratosthenes: http://www.visnos.com/demos/sieve-of-eratosthenes

Named after the Greek Mathematician. This classic method of finding prime numbers is also great for teaching about factors and multiples. The visnos sieve allows for multi colored squares this allows identification of any numbers prime factors.

BBC Bitesize Decomposing numbers into prime factors: http://www.bbc.co.uk/education/clips/zcvw2p3

How to decompose numbers into products of prime factors and a look at simple sequences.

### Student resources.

Two Primes Make One Square: http://nrich.maths.org/1150

Fnd the prime number

Write down the prime number in each group

- 7, 8, 9
- 16, 17, 18
- 21, 22, 23
- 30, 31, 32
- 47, 48, 49
- 57, 58, 59
- 66, 67, 68
- 73, 74, 75
- Find the next prime number after 24.
- Find the next prime number after 37.
- Find all the prime numbers below 50. There are 15. Remember, 1 is not a prime number.

Intel Prime Numbers - Student led ITP: http://inteleducationresources.intel.co.uk/content/primary/maths/prime_numbers/