Factors

# Factors of 18 | What Are Factor Pairs of 18? | Prime Factors of 18

Written by Prerit Jain

Updated on: 12 Aug 2023

Contents

### Factors of 18 | What Are Factor Pairs of 18? | Prime Factors of 18

Factors of 18 are the numbers that divide the number 18 without leaving any remainder. Since 18 is a composite number, it has multiple factors. Let us discuss everything about Factors of 18 and much more. Scroll down to find out more.

## What Are the Factors of 18?

As discussed above, 18 is a composite number, i.e., it has multiple factors. These factors can be either positive or negative. Hence, the number 18 has both positive and negative factors. There are a total of 6 factors for the number 18, which doesn’t leave any remainder after division.

Factors of 18: 1, 2, 3, 6, 9, and 18 |

Negative Factors of 18: -1,-2,-3, -6, -9, and -18 |

Prime Factorization of 18: 2 X 2 X 2 X 2 X 3 or 2^{4} X 3 |

Prime Factors of 18: 2, 3 |

Sum of Factors of 18: 39 |

Sum of Prime Factors of 18: 5 |

## What Are Factor 18 in Pairs?

As we said above, there are 6 factors for the number 18. The 18 factors have both positive and negative pairs. Let us see the positive pair and the negative pair of factors of 18:

### Positive Pair Factors of 18

The positive pair factors of 18 are (1,18), (2, 9), and (3, 6).

### Negative Pair Factors of 18

The negative pair factors of 18 are (-1,1-8), (-2, -9), and (-3, -6).

## How To Factors of 18 by Division Method?

We can find factors of 18 using the division method. Here, basically, we will divide 18 with all the integers till 18. The numbers which leave a remainder are not considered as factors of 18. Whereas the numbers which don’t leave any remainder after dividing are the numbers known as factors of 18. Let us understand how to find factors of 18 using the division method from below:

- 18 ÷ 1 = 18 (Remainder = 0)
- 18 ÷ 2 = 9 (Remainder = 0)
- 18 ÷ 3 = 6 (Remainder = 0)
- 18 ÷ 6 = 3 (Remainder = 0)
- 18 ÷ 9 = 2 (Remainder = 0)
- 18 ÷ 18 = 1 (Remainder = 0)

As you can see, these integers have no remainders after being divided by 18. So that means 1, 2, 3, 6, 9, and 18 are the factors of 18.

## What are the Prime Factors of 18?

As 18 is a composite number, we can also find its prime factors through prime factorization. The detailed steps on how to do this are explained below:

**Step 1:**The first step is to divide 18 with the smallest prime number 18 is divisible by, which is 2.

18 ÷ 2 = 9- Step 2: Now we will divide the number 9 by the smallest prime number it is divisible by. Since 9 is not divisible by 2, we will choose the next smallest prime number which is 3 because we can divide 9 by 3.

9 ÷ 3 = 3 **Step 3:**Now, we will divide 3 by 3, because it is a prime number. So, that means it can only be divided by the number itself.

3 ÷ 3 = 1

Hence the prime factors of **18 are 2 x 3 x 3 = 2 × 3 ^{2}**.

## What is the Factor Tree of 18?

The steps to find the factor tree of 18 are given below:

**Step 1:**Firstly, write the number 18 at the top of the factor tree.**Step 2:**Now, as the tree’s branches, write down the pair factors of 18 for dividing 18. The pair factors we have used here are 2 and 9 because they are divisible by 18.**Step 3:**Since 2 is a prime number, we can not divide it.**Step 4:**But as 9 is a composite number, we will divide it with another pair factor it is divisible by, which is 3, 3.

Hence, the factors of all the numbers are prime numbers so we cannot divide them anymore. Circling all the branches with prime numbers gives us the factors 3, 3, and 2. Therefore, the prime factors of 18 using a factor tree are **2 X 3 X 3 = 18.**

The factor tree of 18 is given below:

## List All the Factors of 18 in Increasing Order

Factors of 18 are 9, 2, 3, 1, and 18

So, in increasing order the factors of 18 will be:**1, 2, 3, 6, 9, and 18.**

## Solved Examples on Factors of 18

The solved examples of factors of 18 are given below:

**What are the factors pairs of 18?**

The pair factors of 18 can be both positive and negative.

The positive pair factors of 18 are (1,18), (2, 9), and (3, 6).

The negative pair factors of 18 are (-1,-18), (-2, -9), and (-3, -6).

**What are the common factors of 9 and 18?**

And the factors of 9 are 1, 3, and 9.

The factors of 18 are 1, 2, 3, 6, 9, and 18.

The common factors of 9 and 18 are 1, 3, and 9.

If we see the GFC of 9 and 18, then 9 is the GFC.

**What are the common factors of 18 and 12?**

The factors of 18 are 1, 2, 3, 6, 9, and 18.

And the factors of 12 are 1, 2, 4, and 12.

Hence, the common factors of 18 and 12 are 1, and 2.

If we see the GFC of 18 and 12, then the GFC is 2.

**What are the common factors between 18 and 30?**

The factors of 18 are 1, 2, 3, 6, 9, and 18.

And the factors of 30 are 1, 2, 3, 5, 6, 10, 15, and 30.

If we see the GFC of 18 and 30, 6 is the GFC.

Hence, the common factors of 18 and 30 are 1, 2, 3, and 6.

**What are the common factors between 18 and 45?**

The factors of 18 are 1, 2, 3, 6, 9, and 18.

And the factors of 45 are 1, 3, 5, 9, 15, and 45.

If we see the GFC of 18 and 45, then 9 is the GFC.

Hence the common factors of 18 and 45 are 1, 3, and 9.

**Which of the following conversion factors would you use to change 18 kilometers to meters?**

As we know that there are 1,000 meters in a kilometer.

Moreover, a Kilometer is 1,000 bigger than a meter.

This says that we can multiply your distance of 18 kilometers by 1,000 to get 18,000.

18 (Kilometres) ÷ 1,000 (Meters) = 18,0000 (Meters)

## FAQs on Factors of 18

**What are the factors of 18 in pairs?**

(1,18), (2, 9), and (3, 6) are the factor pairs of 18.

**What are the factors of -18?**

-1, -2, -3, -6, -9, and -18 are the factors of -18.

**What are the factors and prime factors of 18?**

The factors of 18 are 1, 2, 3, 6, 9, and 18.

The prime factors of 18 are 2 X 3^{2} or 2 X 3 X 3.

**What are all the factors of 18 that are prime numbers?**

1, 2, and 3 are the factors of 18 that are prime numbers.

**What is the set of all factors of 18?**

The factors of 18 written in the format of the set is known as factors of 18.

(1, 2, 3, 6, 9, 18) is the set of factors of 18.

**What are the composite factors of 18?**

6, 9, and 18 are the composite factors of 18.

**What are the common factors of 18 and 9?**

Factors of 18: 1, 2, 3, 6, 9, and 18.

Factors of 9: 1, 3, and 9.

Hence, the common factors of 18 and 9 are 1, 3, and 9.

Also, the least common factor of 18 and 9 is 1.

**Write factors of 18 from least to greatest.**

The factors of 18 from least to greatest will be 1, 2, 3, 6, 9, and 18.

That concludes the topic of factors and the prime factors of 18. We hope that this information has been helpful to you and that you are now able to easily find the factors of 18 and apply all of the methods. Feel free to leave a comment below if you have any questions or concerns regarding this topic. We will get back to you as soon as possible.

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Written by

Prerit Jain