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Last updated on May 26th, 2025

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LCM Of 3, 5 and 15

Professor Greenline Explaining Math Concepts

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 3, 5 and 15 together and what that really means

LCM Of 3, 5 and 15 for US Students
Professor Greenline from BrightChamps

What Is The LCM Of 3, 5 And 15?

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 3, 5 and 15, The LCM is 15. 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 3, 5 And 15

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 3, 5 And 15 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.


step 1: list all the multiples of the given numbers.


Multiples Of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27 and 30.


Multiples Of 5: 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50.


Multiple Of 15: 15, 30, 45, 60, 75, 90, 105, 120, 135 and 150.


step 2: find the smallest common multiples in both the numbers. In this case, that number is 15 as highlighted above.


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

Professor Greenline from BrightChamps

Finding The LCM 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:


3= 3


5= 5


15= 5×3


As 5 and 3 are common, it will be considered only once. We will get the equation as (5×3)


So after the multiplication, we will be getting the LCM as 15.


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 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 3. In that case, we divide the numbers by 3. It will reduce the values of the numbers to 1, 5 and 5.


As 5 is a prime number, it can be divided by themselves. After this step, all the numbers in the last row will be 1.


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: 3 and 5. 


These numbers multiplied give 15. On this basis, therefore, the LCM of the 3, 5 And 15 becomes 15.
 

 

Max Pointing Out Common Math Mistakes

Common Mistakes That Are Made And How To Avoid Them For LCM Of 3, 5 And 15.

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.
 

Max from BrightChamps Saying "Hey"

LCM Of 3,5 and 15 Examples

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

Problem 1

If you have bags of candies: 3, 5, and 15 candies each, how many total candies to distribute equally?

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


You have 15 candies. You can share them equally among different bags, making sure each bag has the same number of candies for everyone.
 

Explanation

There are 3 bags in total, and the total candies are 15. To distribute them equally, divide the candies evenly between the bags. Each bag will have 5 candies



 

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

Problem 2

A party has invites sent out in groups of 3, 5, and 15. How many should be sent to have equal groups?

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

 Fifteen invitations are needed.
 

Explanation

Fifteen is the smallest number that can be divided by 3, 5, and 15 without leaving any extras. This makes it a perfect group size

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

Problem 3

3 kids jump after 3 seconds, 5 kids after 5 seconds, and 15 kids after 15 seconds, how long will they take to all jump at once?

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

After 15 seconds, all the kids will jump together.
 

Explanation

 The jumping times match at 15 seconds because 15 is the smallest number that is a multiple of 3, 5, and 15.
 

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

Problem 4

A toy store has toys in sets of 3, 5, and 15. How many total toys for equal sets?

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

There are 15 toys. You can make 3 sets of 5 toys each or 5 sets of 3 toys each.
 

Explanation

 You can divide 15 toys into equal sets in different ways, like making 3 sets with 5 toys or 5 sets with 3 toys.
 

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

Problem 5

Three friends play games in groups of 3, 5, and 15. How many total games until they play together?

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

They will all play together after 15 games.
 

Explanation

The smallest number that 3, 5, and 15 all divide evenly into is 15. So, after 15 games, they will play together.
 

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

FAQs For LCM Of 3,5 and 15

1.What’s the LCM of 3,5 and 15?

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2.How is the LCM and GCF of 4, 10 and 20?

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3.Is the LCM of 3 and 5 also their HCF?

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4.What is the prime factorization of 15?

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5.How can children in United States use numbers in everyday life to understand LCM Of 3, 5 and 15?

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6.What are some fun ways kids in United States can practice LCM Of 3, 5 and 15 with numbers?

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7.What role do numbers and LCM Of 3, 5 and 15 play in helping children in United States develop problem-solving skills?

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8.How can families in United States create number-rich environments to improve LCM Of 3, 5 and 15 skills?

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Professor Greenline from BrightChamps

Important Glossaries for LCM of 3,5 and 15

  • Least Common Multiple (LCM): The smallest number that can be evenly divided by two or more given numbers.

 

  • Prime Factorization: Breaking down a number into its prime factors, which are the prime numbers that multiply together to give the original number.

 

  • Prime Numbers: Numbers greater than 1 that have no positive divisors other than 1 and themselves (e.g., 2, 3, 5, 7).

 

  • Division Method: A technique for finding the LCM by dividing the given numbers by their prime factors until all are reduced to one.
     
Professor Greenline from BrightChamps

About BrightChamps in United States

At BrightChamps, we believe numbers are more than just figures—they unlock a world full of possibilities! Our goal is to help children throughout the United States master key math skills, focusing today on the LCM Of 3, 5 and 15 with special attention to understanding the LCM—in a way that’s engaging, fun, and easy to grasp. Whether your child is calculating the speed of a roller coaster at Disney World, keeping score during a Little League baseball game, or managing their allowance to save for cool gadgets, knowing numbers builds confidence for everyday life. Our hands-on lessons make learning enjoyable and straightforward. Since kids in the USA have unique learning styles, we customize our methods to match each child’s needs. From the lively streets of New York City to the sunny beaches of California, BrightChamps brings math alive, making it meaningful and exciting all across America. Let’s make the LCM an exciting part of every child’s math adventure!
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Hiralee Lalitkumar Makwana

About the Author

Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.

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Max, the Girl Character from BrightChamps

Fun Fact

: She loves to read number jokes and games.

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