What is the GCF of 15 and 18?
Greatest Common Factor of two or more numbers is the largest possible number which divides the given numbers exactly without any remainder.
Answer: GCF of 15 and 18 is 3
Explanation:
We can find the GCF by the following methods

Prime factorization Method

Listing the common factors Method

Long division Method
GCF of 15 and 18 by Prime Factorization
Let us represent 15 and 18 as a product of their prime numbers:
Prime factorization of 15 is 3 x 5
Prime factorization of 18 is 2 x 3 x 3
Common factors = 3
GCF is the product of the factors that are common to each of the given numbers.
GCF is 3 = 3
GCF of 15 and 18 by Long Division Method

Step 1: Divide 18 by 15 and check the remainder.

Step 2: Make the remainder of the above step as the divisor and the divisor of the above step as the dividend and perform the long division again.

Step 3: Continue till you get remainder as 0
You can find the GCF in any of the above methods but the solution will always remain the same.