A number is a common factor of two or more numbers if it is a factor of all those numbers. Example: Factors of 6 are . Factors of 8 are . Their common factors are

Decompose each number into its prime factors.

Since all common factors of a set of numbers are actually factors of their , it is often faster to: of the numbers. Find all factors of that . These are your common factors. 3. Step-by-Step Guide to Finding ƯCLN To find the of numbers greater than 1, follow these three steps: