Question

What is the GCF OF 21 and 25

Answer 1

Hello!

GCF, or greatest common factor, is the greatest factor shared between two numbers. (A factor is something which you can divide a number by to get a whole number)

To do this, first list out all the factors of 21 and 25. (There are other methods to do this, but, this method will work for smaller numbers)

21: 1, 3, 7, 21

25: 1, 5, 25

As you can see, the greatest factor shared between them is the number 1.

Therefore, the GCF of 21 and 25 is 1.

Hope this helps!

(Side note: a better method to do this for larger numbers is to list out the prime factorization for each number, then find all the numbers in common, and multiply)

Answer 2

THE ANSWER IS 1

Explanation:

if we de compose by prime factors the given numbers we obtain the following:

21=1.3*7

25=1*5*5

from where we can see that the only common factor of these numbers is 1, hence the GCF of 21 and 25 is 1