GCF for 20 and 780

What is the Greatest Common Factor of 20 and 780?

Answer: GCF of 20 and 780 is 20

(Twenty)

Finding GCF for 20 and 780 using all factors (divisors) listing

The first method to find GCF for numbers 20 and 780 is to list all factors for both numbers and pick the highest common one:

All factors of 20: 1, 2, 4, 5, 10, 20

All factors of 780: 1, 2, 3, 4, 5, 6, 10, 12, 13, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390, 780

So the Greatest Common Factor for 20 and 780 is 20

Finding GCF for 20 and 780 by Prime Factorization

The second method to find GCF for numbers 20 and 780 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 20: 2, 2, 5

All Prime Factors of 780: 2, 2, 3, 5, 13

As we can see there are Prime Factors common to both numbers: 2, 2, 5

Now we need to multiply them to find GCF: 2 × 2 × 5 = 20

GCF Table

Number 1Number 2GCF
57805
67806
77801
87804
97803
1078010
117801
1278012
1378013
147802
1578015
167804
177801
187806
197801
2078020
217803
227802
237801
2478012
257805
2678026
277803
287804
297801
3078030
317801
327804
337803
347802

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 20 and 780? (The answer is: 20). Select the first number (e.g. '20') and the second number (e.g. '780'). 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 20 and 780?

GCF of 20 and 780 is 20