# What is the GCF of 18 and 28?

The largest possible number which divides both the numbers exactly is called GCF of two numbers 18 and 28.

## Answer: GCF of 18 and 28 is 2

Let us see how to find the GCF of 18 and 28.

## Explanation

The greatest common factor of two numbers is the largest possible number which divides both the numbers exactly without any remainder.

## Common Methods to Find GCF of 18 and 28

- Prime factorization
- Listing the common factors

### Method 1: GCF of 18 and 28 by Prime Factorization

We represent18 and 28 as a product of its prime factors.

Prime factorization of 18 is 2 × 3 × 3

Prime factorization of 28 is 2 × 2 × 7

Common factor = 2

GCF is the product of the factors that are common to each of the given numbers.

GCF (18,28) is 2.

### Method 2: GCF of 18 and 28 by Listing the Common Factors

In this method,

- we list all the factors of 18 and 28, then identify the common factors.
- The highest among the common factors is the GCF(18,28).

The factors of 18 are 1, 2, 3, 6, 9, 18

The factors of 28 are 1, 2, 4, 7, 14, 28.

Common Factors of 18 and 28: 1, 2.

Greatest common factor= 2

GCF of 18 and 28 is 2

Irrespective of the method, the greatest common factor(GCF) of 18 and 28 is the same.