LCM of 18 and 27
2026-02-28 08:17 Diff
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Last updated on August 5, 2025

The Least common multiple (LCM) is the smallest number that is divisible by the numbers 18 and 27. LCM helps to solve problems with fractions and scenarios like scheduling or aligning repeating cycles of events.

What is the LCM of 18 and 27?

How to find the LCM of 18 and 27 ?

There are various methods to find the LCM, Listing method, prime factorization method and division method are explained below; 
 

LCM of 18 and 27 using the Listing multiples method

To ascertain the LCM, list the multiples of the integers until a common multiple is found. 


Steps 1:Writedown the multiples of each number: 


Multiples of 18 = 18,36,54,...


Multiples of 27 = 27,54,...


Step 2: Ascertain the smallest multiple from the listed multiples of 18 and 27. 


The LCM (Least common multiple) of 18 and 27 is 54. i.e., 54 is divisible by 18 and 27 with no reminder.
 

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LCM of 18 and 27 using the Prime Factorization

This method involves finding the prime factors of each number and then multiplying the highest power of the prime factors to get the LCM.


Step 1: Find the prime factors of the numbers:


Prime factorization of 18 =  2×3×3

Prime factorization of 27= 3×3×3

  Take the highest power of each prime factor and multiply the ascertained factors to get the LCM: 


LCM (18,27) = 54

LCM of 18 and 27 using the Division Method

The Division Method involves dividing the numbers by their prime factors and multiplying the divisors to get the LCM.

Step 1: Write down the numbers in a row;

Step 2: Divide the row of numbers by a prime number that is evenly divisible into at least one of the given numbers. 

Step 3:Continue dividing the numbers until the last row of the results is ‘1’ and bring down the numbers not divisible by the previously chosen prime number.

        Step 4:The LCM of the numbers is the product of the prime numbers in the first column, i.e., 


LCM (18,27) = 54

Common Mistakes and how to avoid them in LCM of 18 and 27

Listed below are a few commonly made mistakes while attempting to ascertain the LCM of 18 and 27, make a note while practicing. 
 

Problem 1

Elaborate on the relationship between HCF and LCM of 18 and 27.

Okay, lets begin

The relationship between HCF and LCM can be verified using this formula; HCF(a,b)×LCM(a,b) = a×b


HCF of 18,27 = 9 


LCM of 18,27 = 54


Now apply the formula, 


HCF(a,b)×LCM(a,b) = a×b


HCF(18,27)×LCM(18,27) = 18×27


9×54 = 18×27


486=486
 

Explanation

The above explains the relationship between the HCF and the LCM of 18 and 27. The given formula works to verify the relationship between the HCF and LCM for any given pair of numbers. 

Well explained 👍

Problem 2

If the HCF of 18 and 27 is 9, using the relationship between 18 and 27, find the LCM.

Okay, lets begin

Given values;

 
HCF = 9


a = 18


b = 27

Explanation

The relationship between HCF and LCM, as explained above allows us to find the LCM without direct calculation. 

Well explained 👍

Problem 3

Trains A and B arrive every 27 minutes and 18 minutes at the station at the same time. In how long will they arrive together again?

Okay, lets begin

The LCM of 18 and 27 =54
 

Explanation

The smallest common multiple is ascertained between the numbers to ascertain the next arrival of the trains at the same time, which is in 54 minutes.

Well explained 👍

FAQ’s on LCM of 18 and 27

1.List the common factors of 18 and 27.

Factors of 18–1,2,3,6,9,18


Factors of 27–1,3,9,27


Common factors between the numbers — 1,3,9
 

2.What is the LCM of 18,27 and 36?

Prime factorization of 18 = 3×3×2


Prime factorization of 27 = 3×3×3


Prime factorization of 36 = 3×3×2×2


LCM (18,27,36) = 108
 

3.What is the LCM of 18,27 and 35?

Prime factorization of 18 = 3×3×2


Prime factorization of 27 = 3×3×3


Prime factorization of 35 = 7×5


LCM (18,27,35) = 1890
 

4.What is the LCM of 18,20,24 and 27?

Prime factorization of 18 = 3×3×2


Prime factorization of 20 = 2×5×2


Prime factorization of 24 = 2×3×3


Prime factorization of 27 = 3×3×3


LCM (18,20,24,27) = 1080
 

5.What is the LCM of 18 and 32?

Prime factorization of 18 = 3×3×2


Prime factorization of 32 = 2×2×2×2×2


LCM(18,32) = 288
 

mportant glossaries for LCM of 18 and 27

  • Multiple: A number and any integer multiplied. 
  • Prime Factor: A natural number (other than 1) that has factors that are one and itself.
  • Prime Factorization: The process of breaking down a number into its prime factors is called Prime Factorization. 
  • Co-prime numbers: When the only positive integer that is a divisor of them both is 1, a number is co-prime. 
  • Relatively Prime Numbers: Numbers that have no common factors other than 1.
  • Fraction: A representation of a part of a whole.
     

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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.

Fun Fact

: She loves to read number jokes and games.