# What is the HCF of 12, 15 and 18?

To find the HCF (Highest Common Factor) of three numbers, we have to determine the largest possible number which divides the three numbers exactly leaving the remainder as 0.

## Answer: HCF of 12, 15, and 18 is 3

Let us see how to find the HCF of 12, 15, and 18

## Explanation:

HCF of 12, 15, and 18 will the highest number that divides 12, 15, and 18 exactly, that is, leaving the remainder 0

We will explain the following two methods to find the HCF of 12, 15 and 18

- Prime factorization Method
- Listing the common factors method

## Methods to Find HCF of 12, 15, and 18

### HCF of 12, 15, and 18 by Prime Factorization

We will express the numbers 12, 15 and 18 as a product of their prime factors.

Prime factorization of 12 is 2 × 2 × 3

Prime factorization of 15 is 3 × 5

Prime factorization of 18 is 2 × 3 × 3

The common factor in the prime factorization of 12, 15 and 18 is 3

HCF is the product of the prime factors that are common to the numbers, 12, 15, and 18

So, HCF of 12, 15, and 18 is 3

### HCF of 12, 15, and 18 by Listing the Common Factors

The factors of 12, 15 and 18 are:

Factors of 12: 1, 2, 3, 4, 6, 12

Factors of 15: 1, 3, 5, 15

Factors of 18: 1, 2, 3, 6, 9, 18

The common factors of 12, 15, and 18 are 1 and 3

The highest common factor of 12, 15, and 18 is 3

So, HCF of 12, 15, and 18 is 3