GCF for 78 and 80

What is the Greatest Common Factor of 78 and 80?

Answer: GCF of 78 and 80 is 2

(Two)

Finding GCF for 78 and 80 using all factors (divisors) listing

The first method to find GCF for numbers 78 and 80 is to list all factors for both numbers and pick the highest common one:

All factors of 78: 1, 2, 3, 6, 13, 26, 39, 78

All factors of 80: 1, 2, 4, 5, 8, 10, 16, 20, 40, 80

So the Greatest Common Factor for 78 and 80 is 2

Finding GCF for 78 and 80 by Prime Factorization

The second method to find GCF for numbers 78 and 80 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 78: 2, 3, 13

All Prime Factors of 80: 2, 2, 2, 2, 5

As we can see there is only one Prime Factor common to both numbers. It is 2

So 2 is the Greatest Common Factor of 78 and 80

Related Calculations

GCF Table

Number 1Number 2GCF
63801
6480
65805
66802
67801
68804
69801
7080
71801
72808
73801
74802
75805
76804
77801
78802
79801
808080
81801
82802
83801
84804
85805
86802
87801
88808
89801
908010
91801
92804

About "Greatest Common Factor" Calculator

This calculator will help you find the greatest common factor (GCF) of two numbers. For example, it can help you find out what is the Greatest Common Factor of 78 and 80? (The answer is: 2). Select the first number (e.g. '78') and the second number (e.g. '80'). After that hit the 'Calculate' button.
Greatest Common Factor (GCF) also known as the Greatest Common Divisor (GCD) or Highest Common Factor (HCF) - it is the largest positive integer that divides each of the integers with zero remainder

FAQ

What is the Greatest Common Factor of 78 and 80?

GCF of 78 and 80 is 2