Greatest Common Factor of 8 and 20 by Prime Factorization

Given Numbers: 8, 20
Identify the Prime Factors of 8 and 20 by Prime Factorization

• Prime Factorization of 8: 8 = 2 x 2 x 2 = 2³
• Prime Factorization of 20: 20 = 2 x 2 x 5 = 2² x 5¹

Determine the Prime Factor(s) that are common to the Prime Factorization of each number:

• 2 is the only Prime Factor common to the Prime Factorizations of 8 and 20

Determine the least number of occurrences of 2 among the Prime Factorizations:

• 2 occurs at least 2 times in each Prime Factorization

As a result, the Greatest Common Factor (GCF) of 8 and 20 is equal to 2 x 2, which equals 2 raised to the power of its least number of occurrences or smallest exponent among the Prime Factorizations:

• GCF(8, 20) = 2² = 2 x 2
• GCF(8, 20) = 4

Therefore, the Greatest Common Factor of 8 and 20 by Prime Factorization = 4