GCD of 78, 55, 21 Calculator

Given Input numbers are 78, 55, 21

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

Divisors of 78

List of positive integer divisors of 78 that divides 78 without a remainder.

1, 2, 3, 6, 13, 26, 39, 78

Divisors of 55

List of positive integer divisors of 55 that divides 55 without a remainder.

1, 5, 11, 55

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 78, 55, 21 . The biggest common divisior number is the GCD number.
So the Greatest Common Divisior 78, 55, 21 is 1.

Therefore, GCD of numbers 78, 55, 21 is 1

Given Input Data is 78, 55, 21

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

Prime Factorization of 78 is 2 x 3 x 13

Prime Factorization of 55 is 5 x 11

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(78, 55) = 4290

GCD(78, 55) = ( 78 x 55 ) / 4290

GCD(78, 55) = 4290 / 4290

GCD(78, 55) = 1

Step2:

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 78, 55, 21 is 1

Here are some samples of GCD of Numbers calculations.

• GCD of 28, 91, 96
• GCD of 95, 46, 24
• GCD of 27, 66, 80
• GCD of 34, 67, 56
• GCD of 93, 73, 23

1. What is the GCD of 78, 55, 21?

GCD of 78, 55, 21 is 1

2. Where do I get the detailed procedure to find GCD of 78, 55, 21?

You can find a detailed procedure to find GCD of 78, 55, 21 on our page.

3. How to find GCD of 78, 55, 21 on a calculator?

You can find the GCD of 78, 55, 21 by simply giving the inputs separated by commas and click on the calculate button to avail the Greatest Common Divisor in less time.