2 x 2 x 2 x 3 = 24
2 x 2 x 7 = 28
2 x 2 = 4, the GCF.
You do a factor rainbow to find a prime factorization. You compare prime factorizations to find a greatest common factor.
7
Finding the greatest common factor helps when you are reducing fractions.
If they have no prime factors in common, their GCF is 1.
Hug
the smaller number
You do not necessarily need the common prime factors when finding the greatest common factor, but with large numbers or numbers for which you cannot easily determine all the factors, using prime factorization to determine the greatest common factor is the easiest method. The greatest common factor can then be determined by multiplying the common prime factors together. For example, when trying to find the greatest common factor of 2144 and 5672, finding all their possible factors to compare could be difficult. So, it is easier to find their prime factors, determine the prime factors they have in common, and then multiply the common prime factors to get the greatest common factor. For descriptions and examples of finding the greatest common factor, see the "Related Questions" links below.
Ah, finding the greatest common factor is like finding a happy little tree in a forest. For 36 and 81, we look for the largest number that can divide evenly into both. The greatest common factor for 36 and 81 is 9, like a gentle breeze on a sunny day.
No.
By finding the factors in both numbers and then finding the one that is greatest in common. For example the G.C.F for 45 and 36 is 9.
2 x 2 = 42 x 5 = 10The GCF is 2.
What makes a greatest common factor "common" is comparing at least two terms and finding something common between them.