How do you find the GCF of 15 , 18 and 30 ?

To find the Greatest Common Factor (GCF) of 15, 18, and 30, follow these steps:

Find the prime factorization of each number:

15: The prime factors of 15 are 3 and 5 (15 = 3 × 5).
18: The prime factors of 18 are 2 and 3 (18 = 2 × 3 × 3).
30: The prime factors of 30 are 2, 3, and 5 (30 = 2 × 3 × 5).
List the common prime factors:

The only common prime factor between all three numbers is 3.
Find the lowest power of the common prime factor:

The power of 3 is the same in all three factorizations, which is 3¹.
Multiply the common prime factors:

Since 3 is the only common factor, the GCF is 3.
Thus, the GCF of 15, 18, and 30 is 3.