There are infinitely many prime factors.
2 and 5 are the prime factors that are common to all multiples of 10.
All numbers have factors. Some factors are prime numbers. These are known as prime factors. Some numbers have some of the same prime factors as other numbers. These are known as common prime factors. 3 is a common prime factor of 12 and 15.
All numbers have factors. Some factors are prime numbers. A prime factor is a factor that is a prime number. A common prime factor is a prime factor that appears on the list of factors of two or more given numbers.
The prime factors of 24 are 2,2,2 and 3 The prime factors of 36 are 2,2,3 and 3 Thus the common factors are 1,2,3,4,6 and 12.
The prime factors of 28 are 2,2 and 7 The prime factors of 42 are 2,3 and 7 Thus the common factors are 1,2,7 and 14.
All numbers have factors. Some numbers have some of the same factors as other numbers. These are common factors. If the factor is a prime number, it is a common prime factor. 3 is a prime number. 3 is a factor of 9. 3 is a factor of 12. 3 is a common prime factor of 9 and 12.
Example: What are the common prime factors of 120 and 252?Find the prime factorization of each number by breaking it down into the lowest possible numbers that can be multiplied together to make the original number.120 = 2x60 = 2x2x30 = 2x2x2x15 = 2x2x2x3x5252 = 2x126 = 2x2x63 = 2x2x3x21 = 2x2x3x3x7Notice that there are 2 2's and a 3 in each factorization: the common prime factors are 2, 2, and 3.
The product of all the common prime factors is the GCF. The product of all common factors would vary according to the list.
They all have two unique factors.
13 is a prime number. The only common factors are 1 and 13.
If it has no prime factors in common. The prime factors of 16 are all twos and the prime factors of 27 are all threes. 16/27 has to be in simplest form.
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.