GCF stands for greatest common factor that is the largest common factor by which two or more numbers can be divided. You can use the following steps to find GCF.
1. Find the prime factorization of each number.
2. Write each number as a product of prime factors.
3. Bring down the primes in each column.
4. Find the greatest common factor.
5. For example the GCF of 12 and 30 is 6.