GCF of 15 and 30
GCF (Greatest Common Factor) of the numbers 15 and 30 is the largest possible number which divides 15 and 30 exactly without any remainder.
Answer: GCF of 15 and 30 is 15
Two methods to find the GCF of 15 and 20 are explained below.
Methods to find GCF of 15 and 30
We can find the GCF by the following two methods:

Listing the common factors Method

Prime factorization Method
Method 1: GCF of 15 and 30 by Listing the Common Factors
Factors of 15: 1, 3, 5, and 15
Factors of 30 : 1, 3, 5, 6, 10, 15, and 30
Common factors of 15 and 30 are 1, 3, 5, and 15
We observe that the greatest common factor of 15 and 30 from the list is 15
So, GCF of 15 and 30 is 15
Method 2: GCF of 15 and 30 by Prime Factorization
Let us represent 15 and 30 as a product of their prime factors:
Prime factorization of 15 is 3 × 5
Prime factorization of 30 is 2 × 3 × 5
The common factors in the prime factorization of 15 and 30 are 3 and 5
GCF is the product of the factors that are common to each of the given numbers.
GCF of 15 and 30 is 3 × 5 = 15
You can find the GCF in any of the above methods but the solution will always remain the same.