Find the greatest common factor (GCF).

Question

21 and 27

Answer 1

To find the greatest common factor (GCF) of 21 and 27, we can start by finding the factors of each number.

The factors of 21 are:

• 1
• 3
• 7
• 21

The factors of 27 are:

• 1
• 3
• 9
• 27

Now, we identify the common factors between the two lists. The common factors of 21 and 27 are:

• 1
• 3

The greatest of these common factors is 3.

So, the GCF of 21 and 27 is 3.