# What is the GCF of 28 and 42?

The greatest common factor of two or more numbers is the maximum possible number that divides the given numbers exactly.

## Answer: GCF of 28 and 42 is 14

Two methods to find the GCF of 28 and 42 are explained below.

## Methods to find GCF of 28 and 42

We can calculate the greatest common factor(GCF), by the following methods

- Prime factorization Method
- Listing the common factors method
- Long division Method

### Method1: Calculate GCF of 28 and 42 by Prime Factorization

Let us represent 28 and 42 as a product of its prime numbers

Prime factorization of 28 is 2 × 2 × 7

Prime factorization of 42 is 2 × 3 × 7

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

### Method2: GCF of 28 and 42 by Listing the Common Factors

Factors of 28: 1, 2, 4, 7, 14 and 28

Factors of 42 : 1, 2, 3, 6, 7, 14, 21 and 42

Common Factors of 28 and 42 :1, 2, 7 and 14

GCF of 28 and 42 is 14

### Method3: Calculate GCF of 28 and 42 by Long Division

Step 1: Divide 42 by 28 and check the remainder.

Step 2: The remainder of the above step is the divisor for the next step and the dividend for the next step is the divisor of the above step

Step 3: Continue the process till you get the remainder as 0

The GCF of two numbers is unique as it is independent of the method we opt for.