Best Answer

the greatest common factor is 7,

because 21 divided by 7 is 3,

28 divided by 7 is 4

and 56 divided by 7 is 8.

Q: What are the greatest common factors of 21 and 28 and 56?

Write your answer...

Submit

Still have questions?

Continue Learning about Math & Arithmetic

The common factors are: 1, 2 The Greatest Common Factor (GCF) is: 2

7

7

Factors of 21: 1, 3, 7, 21.Factors of 308: 1, 2, 4, 7, 11, 14, 22, 28, 44, 77, 154, 308.GCF (21, 308) = 7

The GCF is 7.

Related questions

7

The common factors are 1 and 7. The GCF is 7.

The GCF of 21 and 28 is 7.One way to determine the greatest common factor is to find all the factors of the numbers and compare them.The factors of 21 are 1, 3, 7, and 21.The factors of 28 are 1, 2, 4, 7, 14, and 28.The common factors are 1 and 7. Therefore, the greatest common factor is 7.The greatest common factor can also be calculated by identifying the common prime factors and multiplying them together.The prime factors of 21 are 3 and 7.The prime factors of 28 are 2, 2, and 7.The prime factors in common are a single 7, so the greatest common factor is 7.77There is neither a greatest common factor nor common factors of a single number, such as 2821, because there cannot be any form of common factor without two or more numbers to compare. Common factors are factors that the numbers being compared have in common. The greatest common factor is the largest factor that all the numbers being compared have in common. Thus, since there are not two or more numbers to compare, there are neither common factors nor a greatest common factor.

The Greatest Common Factor of 15, 21, 28: 1

the greatest common factor is 7, because 21 divided by 7 is 3, 28 divided by 7 is 4 and 56 divided by 7 is 8.

28

The greatest common factor is 4

Factors of 28... 1,2,4,7,14,28 Factors of 42... 1,2,3,6,7,14,21,42 GCF = 14

To determine the least common multiple of two numbers, determine the prime factors of both number. Then, determine the prime factors they have in common. Multiply all their prime factors together (in other words, multiply both numbers together) and divide by the prime factors they have in common (in other words, their greatest common factor). The prime factors of 21 are 3 and 7. The prime factors of 28 are 2, 2, and 7. The prime factors in common are a single 7. Therefore, the lowest common multiple is 21 x 28 ÷ 7 = 84

The factors of 28 are: 1, 2, 4, 7, 14, 28.The factors of 42 are: 1, 2, 3, 6, 7, 14, 21, 42.The factors of 56 are: 1, 2, 4, 7, 8, 14, 28, 56.The common factors are: 1, 2, 7, 14The greatest common factor is 14

28

The factors of 84 are:1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84The factors of 105 are:1, 3, 5, 7, 15, 21, 35, 105The common factors are:1, 3, 7, 21The Greatest Common Factor (GCF) is:21