# What is the GCF of 42 and 63?

Greatest Common Factor: GCF of two or more numbers is the largest number that can divide the given numbers exactly without any remainder or leaving a remainder zero.

## Answer: GCF of 42 and 63 is 21

Two methods to find the GCF of 42 and 63 are explained below.

## Methods to find GCF of 42 and 63

- Prime factorization Method
- Long division Method

### Method1: GCF of 42 and 63 by Prime Factorization

Let us represent 42 and 63 as a product of its prime factors.

Prime factorization of 42 is 2 × 3 × 7

Prime factorization of 63 is 3 × 3 × 7

Common factors = 3 × 7

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

GCF = 21

### Method2: GCF of 42 and 63 by Long Division

- Step 1: Divide 63 by 42 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 performing the division till you get remainder as zero.

You can find the GCF in any of the above methods but the solution will be the same.

### Therefore, GCF of 42 and 63 = 21

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