Greatest Common Factor of 15 and 28

Created By : Jatin Gogia

Reviewed By : Rajasekhar Valipishetty

Last Updated : Apr 06, 2023

Make use of GCF Calculator to quickly find the Greatest Common Factor of numbers 15, 28 i.e. 1 largest integer by which both the numbers can be divided.

Greatest common factor (GCF) of 15 and 28 is 1.

GCF(15,28) = 1

GCF of 15 and 28

Greatest common factor or Greatest common divisor (GCD) can be calculated in following way;

GCF of:
and

Greatest Common Factor of 15 and 28

GCF of 15 and 28 is 1

Prime Factorization of 15


3 15
5 5
1

Prime factors of 15 are 3,5. Prime factorization of 15 in exponential form is:

15 = 31×51

Prime Factorization of 28


2 28
2 14
7 7
1

Prime factors of 28 are 2,7. Prime factorization of 28 in exponential form is:

28 = 22×71

∴ So by taking common prime factors GCF of 15 and 28 is 1

Greatest Common Factor of 15 and 28 by matching factors method

Factors of 15

List of positive integer factors of 15 that divides 15 without a remainder.

1,3,5,15

Factors of 28

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

1,2,4,7,14,28

Greatest Common Factor

We found the factors and prime factorization of 15 and 28. The biggest common factor number is the GCF number.
So the greatest common factor 15 and 28 is 1.

Also check out the Least Common Multiple of 15 and 28

Properties of GCF 15 and 28

(i) The GCF of 15 and 28 is associative

GCF of 15 and 28 = GCF of 28 and 15

Related Greatest Common Factor of 15

Related Greatest Common Factor of 28

Frequently Asked Questions on GCF of 15 and 28

1. What is the GCF of 15 and 28?

Answer: GCF of 15 and 28 is 1.

2. What are the Factors of 15?

Answer: Factors of 15 are 1, 3, 5, 15. There are 4 integers that are factors of 15. The greatest factor of 15 is 15.

3. What are the Factors of 28?

Answer: Factors of 28 are 1, 2, 4, 7, 14, 28. There are 6 integers that are factors of 28. The greatest factor of 28 is 28.

4. How to Find the GCF of 15 and 28?

Answer:

Greatest Common Factor of 15 and 28 = 1

Step 1: Find the prime factorization of 15

15 = 3 x 5

Step 2: Find the prime factorization of 28

28 = 2 x 2 x 7

Step 3: Multiply those factors both numbers have in common in steps i) or ii) above to find the gcf:

GCF = = 1

Step 4: Therefore, the greatest common factor of 15 and 28 is 1