Greatest Common Factor:
The largest factor which will go into two or more integers.

What can you use this for?
  • finding common factors of polynomials
  • reducing awkward fractions
  • determining the Least Common Multiple (LCM). The LCM is often called the lowest common denominator when we want to add fractions
Amazing fact:
for 2 integers a and b,   LCM • GCF = a•b
Methods for finding the GCF
  1. List all the factors, find the largest in common
  2. List prime factors only, get those in common
  3. Euler's method
Example: What is the GCF of 48 and 54?

back to slideshow central GCF page