# Calculate the GCF of 9 and 30

The greatest common factor, sometimes also called the highest common factor of two positive integers is the largest divisor common to them

## Answer: The GCF of 9 and 30 is 3

Let us see how to find the GCF of 9 and 30

## Explanation:

We can find the GCF by the following two methods:

- By listing factors
- Long Division method

### Method 1: By listing factors

- The factors of 9 and 30 will be listed
- The greatest common factor will be the GCF

Here are the factors of 9 and 30 listed

Factors of 9 = 1,3,9...

Factors of 30 = 1,2,3,5,6,10 ...

The greatest factor among them is 3

Thus, the GCF of 9 and 30 is 3

### Method 2: Long Division method

**Step I: **

Divide the larger number by the smaller one.

**Step II: **

Then the remainder is treated as divisor and the divisor as dividend.

**Step III: **

Divide the first divisor by the first remainder.

**Step IV:**

Divide the second divisor by the second remainder.

**Step V:**

Continue this process till the remainder becomes 0.

**Step VI:**

The divisor which does not leave a remainder is the H.C.F. or G.C.F. of the two numbers and thus, the last divisor is the required greatest common factor (G.C.F) of the given numbers.