GCF for 30 and 81

What is the Greatest common Divisor of 30 and 81?

Answer: GCF of 30 and 81 is 3

(Three)

Finding GCF for 30 and 81 using all factors (divisors) listing

The first method to find GCF for numbers 30 and 81 is to list all factors for both numbers and pick the highest common one:

All factors of 30: 1, 2, 3, 5, 6, 10, 15, 30

All factors of 81: 1, 3, 9, 27, 81

So the Greatest Common Factor for 30 and 81 is 3

Finding GCF for 30 and 81 by Prime Factorization

The second method to find GCF for numbers 30 and 81 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 30: 2, 3, 5

All Prime Factors of 81: 3, 3, 3, 3

As we can see there is only one Prime Factor common to both numbers. It is 3

So 3 is the Greatest Common Factor of 30 and 81

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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 Divisor of 30 and 81? (The answer is: 3). Select the first number (e.g. '30') and the second number (e.g. '81'). 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

GCF Table

Number 1Number 2GCF
15813
1681
17811
1881
19811
20811
2181
22811
23811
24813
2581
26811
2781
2881
29811
3081
31811
3281
33813
34811
35811
3681
37811
38811
39813
40811
41811
42813
43811
44811

FAQ

What is the Greatest common Divisor of 30 and 81?

GCF of 30 and 81 is 3