GCD of 28, 18, 23, 21 Calculator

Given Input numbers are 28, 18, 23, 21

To find the GCD of numbers using factoring list out all the divisors of each number

Divisors of 28

List of positive integer divisors of 28 that divides 28 without a remainder.

1, 2, 4, 7, 14, 28

Divisors of 18

List of positive integer divisors of 18 that divides 18 without a remainder.

1, 2, 3, 6, 9, 18

Divisors of 23

List of positive integer divisors of 23 that divides 23 without a remainder.

1, 23

Divisors of 21

List of positive integer divisors of 21 that divides 21 without a remainder.

1, 3, 7, 21

Greatest Common Divisior

We found the divisors of 28, 18, 23, 21 . The biggest common divisior number is the GCD number.
So the Greatest Common Divisior 28, 18, 23, 21 is 1.

Therefore, GCD of numbers 28, 18, 23, 21 is 1

Given Input Data is 28, 18, 23, 21

Make a list of Prime Factors of all the given numbers initially

Prime Factorization of 28 is 2 x 2 x 7

Prime Factorization of 18 is 2 x 3 x 3

Prime Factorization of 23 is 23

Prime Factorization of 21 is 3 x 7

The above numbers do not have any common prime factor. So GCD is 1

Step1:

Let's calculate the GCD of first two numbers

The formula of GCD is GCD(a, b) = ( a x b) / LCM(a, b)

LCM(28, 18) = 252

GCD(28, 18) = ( 28 x 18 ) / 252

GCD(28, 18) = 504 / 252

GCD(28, 18) = 2

Step2:

Here we consider the GCD from the above i.e. 2 as first number and the next as 23

The formula of GCD is GCD(a, b) = ( a x b) / LCM(a, b)

LCM(2, 23) = 46

GCD(2, 23) = ( 2 x 23 ) / 46

GCD(2, 23) = 46 / 46

GCD(2, 23) = 1

Step3:

Here we consider the GCD from the above i.e. 1 as first number and the next as 21

The formula of GCD is GCD(a, b) = ( a x b) / LCM(a, b)

LCM(1, 21) = 21

GCD(1, 21) = ( 1 x 21 ) / 21

GCD(1, 21) = 21 / 21

GCD(1, 21) = 1

GCD of 28, 18, 23, 21 is 1

Here are some samples of GCD of Numbers calculations.

• GCD of 23, 80, 82, 47
• GCD of 51, 61, 22, 55
• GCD of 77, 41, 19, 12
• GCD of 21, 39, 67, 94
• GCD of 78, 71, 10, 83

1. What is the GCD of 28, 18, 23, 21?

GCD of 28, 18, 23, 21 is 1

2. Where do I get the detailed procedure to find GCD of 28, 18, 23, 21?

You can find a detailed procedure to find GCD of 28, 18, 23, 21 on our page.

3. How to find GCD of 28, 18, 23, 21 on a calculator?

You can find the GCD of 28, 18, 23, 21 by simply giving the inputs separated by commas and click on the calculate button to avail the Greatest Common Divisor in less time.