LCM, HCF and Venn diagrams

• How to work out the LCM and HCF:

  1. Work out the prime factorisation for both numbers
  2. Put the prime numbers in a venn diagram.
  3. HCF - product of shared factors, which is the all of the numbers in the middle of the venn diagram multiplied.
  4. LCM - product of all factors in the venn digram, which is all the of the numbers in the whole diagram multiplied.
• Simpler example:

  
• The HCF is - 15

  The LCM is - 90

  
• The HCF is - 20

  The LCM is - 1200