GCF for 18 and 15

"Greatest Common Factor" Calculator

Greatest Common Factor of

and

What is the Greatest common Divisor of 18 and 15?

Answer: GCF of 18 and 15 is 3

(Three)

Finding GCF for 18 and 15 using all factors (divisors) listing

The first method to find GCF for numbers 18 and 15 is to list all factors for both numbers and pick the highest common one:

All factors of 18: 1, 2, 3, 6, 9, 18

All factors of 15: 1, 3, 5, 15

So the Greatest Common Factor for 18 and 15 is 3

Finding GCF for 18 and 15 by Prime Factorization

The second method to find GCF for numbers 18 and 15 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 18: 2, 3, 3

All Prime Factors of 15: 3, 5

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 18 and 15

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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 18 and 15? (The answer is: 3). Select the first number (e.g. '18') and the second number (e.g. '15'). 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

"Greatest Common Factor" Calculator

Greatest Common Factor of

and

GCF Table

Number 1Number 2GCF
3153
4151
5155
6153
7151
8151
9153
10155
11151
12153
13151
14151
151515
16151
17151
18153
19151
20155
21153
22151
23151
24153
25155
26151
27153
28151
29151
301515
31151
32151

FAQ

What is the Greatest common Divisor of 18 and 15?

GCF of 18 and 15 is 3

See Also