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Last updated on May 26th, 2025

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LCM Of 8,12 and 20

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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 8,12 and 20 together and what that really means.

LCM Of 8,12 and 20 for Qatari Students
Professor Greenline from BrightChamps

What Is The LCM Of 8,12 And 20?

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 8,12 and 20, The LCM is 120. 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 8,12 and 20

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 8,12 and 20 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 8: 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 104, 112, 120, 128 and 136.


Multiples Of 12: 12, 24, 36, 48, 60, 72, 84, 96, 108 and 120. 


Multiples Of 20: 20, 40, 60, 80, 100, 120, 140, 160, 180 and 200.

 

  • The second step is to find the smallest common multiples in both the numbers. In this case, that number is 120 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:


8= 2×2×2


12= 2×2×3


20=2×2×5


As you can see, 2 appears as a prime factor in all three numbers. So instead of considering 2 seven times, we will only consider it three times. So the final equation will look like (2×2×2×3×5).


So after the multiplication, we will be getting the LCM as 120.


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:

 

Step 1: 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 4, 6 and 10.


Step 2: We will divide the numbers by 2 again, now it will become 2,3 and 50. As these numbers are prime numbers, it can only be divided by the number itself. After that, one 1’s will be in the last line.


Step 3: 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: 2,2,2,3 and 5. 


These numbers multiplied give 120. On this basis, therefore, the LCM of the 8,12 and 20 becomes 120.
 

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Common Mistakes And How To Avoid Them in LCM Of 8,12 And 20.

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,
 

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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 8,12 And 20 Examples

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Max, the Girl Character from BrightChamps

Problem 1

Three kids run laps: There is one that runs every eight minutes, one that runs every twelve minutes, and the last that runs every twenty minutes. When will they all meet?

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They will all meet after 120 minutes.
 

Explanation

 120 is the smallest number that can be divided by 8, 12, and 20. This is called the least common multiple (LCM).
 

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Max, the Girl Character from BrightChamps

Problem 2

Three school buses leave at different times: one every 8 minutes, one every twelve minutes, and the last every 20 minutes. When do they leave together?

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They leave together every 120 minutes.
 

Explanation

 The buses leave together every 120 minutes because 120 is the smallest number that can be evenly divided by 8, 12, and 20.
 

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Max, the Girl Character from BrightChamps

Problem 3

If a baker bakes cookies every 8, 12, and 20 minutes, when will they bake together?

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The cookies will bake together every 120 minutes, or 2 hours.
 

Explanation

 The baker bakes cookies every 8, 12, and 20 minutes. The smallest time when they all bake together is 120 minutes.
 

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Max, the Girl Character from BrightChamps

Problem 4

Three cars start a race: one every 8, another every 12, and the last every 20 minutes. When do they race together?

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The cars will race together after 120 minutes.
 

Explanation

120 is the smallest number that fits perfectly into 8, 12, and 20 minutes. This means all cars will start at the same time after 120 minutes.
 

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Max, the Girl Character from BrightChamps

Problem 5

When should they be planted together if a gardener plants flowers 8, 12, and 20 days apart?

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 They should all be planted together every 120 days.

Explanation

 Since 120 is the smallest number that can be divided evenly by 8, 12, and 20, they all plant together after 120 days.
 

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FAQs For LCM Of 8,12 And 20

1.By what method can you compute the LCM of 8, 12, and 20?

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2.Can you give some common multiples of 8, 12, and 20?

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3.Can I find LCM using a number line?

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4.Is LCM possible to be more than both numbers.

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5.How can children in Qatar use numbers in everyday life to understand LCM Of 8,12 and 20?

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6.What are some fun ways kids in Qatar can practice LCM Of 8,12 and 20 with numbers?

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7.What role do numbers and LCM Of 8,12 and 20 play in helping children in Qatar develop problem-solving skills?

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8.How can families in Qatar create number-rich environments to improve LCM Of 8,12 and 20 skills?

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Professor Greenline from BrightChamps

Important Glossaries for LCM of 8,12 and 20

  • Multiple: A number you get when you multiply a number by a whole number. For example, the multiples of 2 are 2, 4, 6, 8, and so on.

 

  • Divisibility: When one number can be divided by another number without leaving a remainder. For instance, 15 is divisible by 3 because 15÷3=5.

 

  • Prime Factorization: Breaking down a number into its basic building blocks, which are prime numbers. For example, 12 can be broken down into 2×2×3.

 

  • Divisor: A number that divides another number evenly. For example, 4 is a divisor of 12 because 12÷4=3.
Professor Greenline from BrightChamps

About BrightChamps in Qatar

At BrightChamps, numbers represent more than digits—they unlock countless opportunities! Our goal is to help children throughout Qatar master important math skills, focusing on the LCM Of 8,12 and 20 with special attention on understanding the LCM—in a lively, fun, and easy way. Whether your child is calculating how fast a roller coaster moves at Qatar’s Angry Birds World, keeping score at local football matches, or managing their allowance to buy gadgets, mastering numbers builds confidence for daily challenges. Our interactive lessons make learning enjoyable and simple. Because children in Qatar learn in many different ways, we adapt our approach to suit each learner. From Doha’s modern cityscape to desert landscapes, BrightChamps makes math come alive. Let’s make the LCM a fun part of every child’s learning!
INDONESIA - Axa Tower 45th floor, JL prof. Dr Satrio Kav. 18, Kel. Karet Kuningan, Kec. Setiabudi, Kota Adm. Jakarta Selatan, Prov. DKI Jakarta
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VIETNAM (Office 1) - Hung Vuong Building, 670 Ba Thang Hai, ward 14, district 10, Ho Chi Minh City
VIETNAM (Office 2) - 143 Nguyễn Thị Thập, Khu đô thị Him Lam, Quận 7, Thành phố Hồ Chí Minh 700000, Vietnam
Dubai - BrightChamps, 8W building 5th Floor, DAFZ, Dubai, United Arab Emirates
UK - Ground floor, Redwood House, Brotherswood Court, Almondsbury Business Park, Bristol, BS32 4QW, United Kingdom