How do you find the GCF of 13 and 26?

Answer 1

Method 1:

Find the factors of both numbers.

13: 1;13

26: 1;2;13;26

The greatest number after the ":" (called a colon) that both numbers have in common is the GCF, or Greatest Common Factor

Method 2:

Use a factor tree (better for integers and larger numbers) to find prime factorization

13
^
1, 13


26
^
2, 13< both are prime numbers, list them.


Prime Factorization
|
V
13:1x13

26:2x13


13 is the greatest common factor.