1

Meaning

2, 7 and 14 are common factors of 28, 42 and 70; 14 is the greatest of the three common factors. We say that 14 is the highest common factor of 28, 42 and 70. HCF is short for Highest Common Factor.
2

Procedure

To find the HCF of a set of numbers: a. express the numbers as a product of prime factors; b. find the common prime factors; c. multiply the common prime factors together to give the HCF.
3

Example

Find the HCF of 18, 24 and 42. 18 = 2 x 3 x 3 24 = 2 x 2 x 2 x 3 42 = 2 x 3 x 7 The common prime factors are 2 and 3. The HCF = 2 x 3 = 6.
o
To test your knowledge in this module, schedule in a weekend test to enjoy:
  1. Assessment tests covering all topics covered
  2. Detailed solutions and insights
  3. Timed self-paced exercises testing your knowledge
  4. Progress reports and analysis

Get Started
Why go into that exam or study without knowing what you don't know? Schedule a test every