GCF of 7 and 21
Reviewed By : Phani Ponnapalli
Last Updated at : Mar 29,2023
Want to know what the GCF of 7 and 21 is? We will not only show you the answer but will also teach you two different methods through which you can easily find the greatest common factor of 7 and 21. Otherwise, you can utilise our handy GCF Calculator tool to quickly get the result.
Detailed Solution to Calculate GCF of 7, 21 using Factoring
In this method, we have to list the factors of 7 and 21 separately and then select the highest number that appears in both lists. This will be your greatest common factor.
The factors of 7 are 1 , and 7
The factors of 21 are 1 , 3 , 7 , and 21
As you can see from the aforementioned lists, the largest number that is present in both lists is 7. Therefore, we can determine that the GCF of 7 and 21 is 7.
Greatest Common Factor of 7, 21 with Prime Factorization
This is prime factorization. Essentially, you have to divide both 7 and 21 with the same prime number and keep going until the numbers can no longer be divided by the same prime number. At that point, you must stop the process and multiply the prime numbers on the left side. The result will be the greatest common factor.
| 7 | 7, 21 |
| 1, 3 |
From the picture, we can see that 1 and 3 cannot be divided by the same number again. So, all we have to do is now multiply the prime numbers on the left.
7 = 7
Hence, the GCF of 7 and 21 is 7.
Find the GCF of 7 and 21
Given numbers are 7 and 21
To find the greatest common factor of 7 and 21
The GCF of 7 and 21 is 7.
FAQs on GCF of 7 and 21
1. What are the LCM and GCF of 7 and 21?
The LCM and GCF of 7 and 21 are 21 and 7.
2. How to get the GCF of 7 and 21?
The GCF of 7 and 21 can be calculated by finding the factors of both numbers and identifying the highest common factor in both.
3. What are the Methods to Find GCF of 7, 21?
The 2 different methods to find the greatest common factor of 7 and 21 are prime factorization and factors of both numbers.