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Last updated on May 26th, 2025

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LCM Of 4 And 18

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The Least Common Multiple (LCM) is the smallest number that when we divide by two or more numbers at a time, all three or more numbers divide into it. LCM also helps in math problems and everyday things like event planning or buying supplies. We will find the LCM of 4 and 18 together and what that really means.

LCM Of 4 And 18 for Australian Students
Professor Greenline from BrightChamps

What Is The LCM Of 4 And 18?

The LCM or the least common multiple of 2 numbers is the smallest number that appears as a multiple of both numbers. In case of 4 and 18, The LCM is 36. But how did we get to this answer? There are different ways to obtain a LCM of 2 or more numbers. Let us take a look at those methods.
 

Professor Greenline from BrightChamps

How To Find The LCM Of 4 And 18

Remember that we previously said there are plenty of ways to calculate the LCM of two numbers or more. Then some of those methods make it extremely easy for us to find the LCM of any two numbers. Those methods are: 

 

  • Listing of Multiples

 

  • Prime Factorization

 

  • Division Method

 

Finally, now we will learn how each of these methods can help us to calculate LCM of given numbers.
 

Professor Greenline from BrightChamps

Finding LCM Of 4 And 18 By Listing Of Multiples

This method will help us find the LCM of the numbers by listing the multiples of the given numbers. Let us take a step by step look at this method.


The first step is to list all the multiples of the given numbers. 


Multiples Of 4: 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 68, 72, 76, 80.


Multiples Of 18: 18, 36, 54, 72, 90, 108, 126, 144, 162, and 180.


The second step is to find the smallest common multiples in both the numbers. In this case, that number is 36 as highlighted above.


By this way we will be able to tell the LCM of given numbers.
 

Professor Greenline from BrightChamps

Finding The LCM of 4 and 18 By Prime Factorization

Let us break down the process of prime factorization into steps and make it easy for children to understand.
The first step is to break down the given numbers into its primal form. The primal form of the number is:


4= 2×2


18= 3×3×2


As you can see, 2 appears as a prime factor in both numbers. So instead of considering 2 three times, we will only consider it twice. So the final equation will look like (3×3×2×2).


So after the multiplication, we will be getting the LCM as 36.


As you can see, using this method can be easier for larger numbers compared to the previous method. 
 

Professor Greenline from BrightChamps

Finding The LCM of 4 and 18 By Division Method

The method to calculate the LCM is really simple. We’ll break these given numbers apart till it comes down to one, by dividing it by the prime factors. The product of the divisors that will come is the LCM of the given numbers.


Let us understand it step by step:

 

  • The first thing is to find the number common in both the numbers. Here it is 2. In that case, we divide both the numbers by 2. It will reduce the values of the numbers to 2 and 9.

 

  • 2 is a prime number, it can be divided by only 2. That means 9 is left by dividing that.

 

  • 3 is a factor of 9 and 9 can be divided by 3. Then, we will have 3. That being said, we’ll end up dividing by 3 again and only have one in the last row.

 

  • This is the end of division. However, we will now find the product of the numbers on the left. The numbers on the left side are: 2,2,3 and 3. 


These numbers multiplied give 36. On this basis, therefore, the LCM of the 4 and 18 becomes 36.
 

Max Pointing Out Common Math Mistakes

Common Mistakes and How to Avoid Them in LCM of 4 and 18

Let us look at some of the common mistakes that can happen while solving a given assignment regarding LCM.
 

Mistake 1

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Missing a prime factor,
 

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

Children sometimes may forget to write all the prime factors for a given number. So, at the start we have to write all the prime factors for the given numbers which won’t cause any problems later on.
 

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LCM Of 4 And 18 Examples.

Ray, the Character from BrightChamps Explaining Math Concepts
Max, the Girl Character from BrightChamps

Problem 1

John and Sally plant trees every 4 and 18 days. When will they plant together?

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John and Sally will plant trees together every 36 days because 36 is the smallest number that both 4 and 18 can fit into.
 

Explanation

To find when they plant together, we use the least common multiple of 4 and 18, which is 36. This means every 36 days.
 

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Max, the Girl Character from BrightChamps

Problem 2

A train arrives every 4 hours, another every 18. How often are we together?

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The trains arrive together every 36 hours because 36 is the smallest time both trains meet.
 

Explanation

Every 4 and 18 hours, the trains return. Finding the smallest number both go into—36—tells us when they’ll arrive together.
 

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 3

If a bus and a taxi arrive every 4 and 18 minutes, when together?

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

 The bus and taxi will arrive together every 36 minutes, since 36 is the smallest time that both 4 and 18 can divide evenly.
 

Explanation

 To find when both arrive together, we find the smallest number that both 4 and 18 divide into, called the Least Common Multiple (LCM). Here, it’s 36.

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 4

What’s the smallest multiple of 4 and 18 that is a 2-digit number?

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

The smallest two-digit number that both 4 and 18 divide evenly is 36.
 

Explanation

Find the smallest number that both 4 and 18 can divide with no remainder. Here, that number is 36, the least common multiple (LCM).
 

Max from BrightChamps Praising Clear Math Explanations
Max, the Girl Character from BrightChamps

Problem 5

At a party, drinks are served every 4 minutes and snacks every 18.

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"

 Drinks and snacks are served together every 36 minutes, as this is the first time they match up due to their serving intervals.

Explanation

Since drinks are served every 4 minutes and snacks every 18, 36 is the smallest number that both fit into evenly, making it the overlap.
 

Max from BrightChamps Praising Clear Math Explanations
Ray Thinking Deeply About Math Problems

FAQs For LCM Of 4 And 18

1.What makes 36 the LCM of 4 and 18?

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2.How do you find the LCM of 4 and 18 using prime factorization?

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3.What is the difference between LCM and GCF for 4 and 18?

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4.How does finding multiples help determine the LCM of 4 and 18?

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5.Can we use the GCF of 4 and 18 to find their LCM?

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6.How can children in Australia use numbers in everyday life to understand LCM Of 4 And 18?

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7.What are some fun ways kids in Australia can practice LCM Of 4 And 18 with numbers?

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8.What role do numbers and LCM Of 4 And 18 play in helping children in Australia develop problem-solving skills?

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9.How can families in Australia create number-rich environments to improve LCM Of 4 And 18 skills?

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Professor Greenline from BrightChamps

Important Glossaries for LCM of 4 and 18

  • Least Common Multiple (LCM): That smallest number of numbers that two or more numbers can share as a multiple. For example, the LCM of 4 and 18 is 36.

 

  • Prime Number: A number that is more than 1, has no divisors other than 1 and itself. The four are 2, 3, 5 and 7.

 

  • GCF (Greatest Common Factor): The largest number divisible by two or more numbers. The GCF of 4 and 18 is 2 for example.

 

  • Prime Factorization: Reducing a number down to its prime factors. The example of prime factorization 18= 2 × 3 × 3 or 2 × 32.
     
Professor Greenline from BrightChamps

About BrightChamps in Australia

At BrightChamps, numbers mean more than just figures—they open up a world of possibilities! Our mission is to help children throughout Australia develop key math skills, focusing on the LCM Of 4 And 18 with a special focus on understanding the LCM—in an engaging, fun, and easy-to-learn way. Whether your child is figuring out how fast a roller coaster runs at Luna Park Sydney, keeping track of cricket scores, or managing their allowance for the latest gadgets, mastering numbers builds confidence in everyday situations. Our interactive lessons make learning enjoyable and straightforward. Because kids in Australia learn in many different ways, we customize our teaching to suit each child. From Sydney’s vibrant streets to the stunning beaches of the Gold Coast, BrightChamps brings math alive, making the LCM an exciting part of every child’s journey!
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