LCM of 3 and 18
2026-02-28 08:37 Diff
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Last updated on August 5, 2025

The smallest number that should also be a positive number, and evenly divide both the numbers, is known as the least common factor. LCM is very important for solving problems, especially fractions, scheduling events etc.

What is the LCM of 3 and 18

The LCM of 3 and 18 is the lowest number that divides both 3 and 18 without leaving any remainder. The LCM of 3 and 18 is 18.
 

How to find the LCM of 3 and 18?

LCM of 3 and 18 using Division method:

In the division method, we divide both the numbers by the lowest possible number until we get 1 for both numbers.

3 divides 3 and 18, leaving 1 and 6


3 divides 6 leaving 2


2 divides 2 leaving 1

LCM = 2 × 3  × 3= 18.
 

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LCM of 3 and 18 using Listing multiples:

We write the multiples of both numbers till we find the common one.


Multiples of 3: 3, 6, 9, 12, 15, 18, 21…


Multiples of 18: 18, 36, 54…


The common multiple is 18. So, the LCM of 3 and 18 is 18.
 

LCM of 3 and 18 using prime factorization:

We part each number into divisors and select the highest powers of all the prime factors.

3=  3


18= 2 × 3 × 3

LCM = 2 × 3 × 3= 18.
 

Common Mistakes and How to Avoid Them in LCM of 3 and 18

While solving problems on LCM children are likely to make common mistakes, here are a few mistakes and how to avoid them.
 

Problem 1

If the LCM of 3 and a number x is 18, what is the value of x?

Okay, lets begin

LCM(3,x) = 18


Using the formula: LCM(a, b) x GCF(a, b) = a × b


Here, a =3 , b =18


GCF(3,x)=3


18 × 3 = 3 x x


54=3x


x=18
 

Explanation

The value of x is 18. Since the LCM of 3 and 18 is indeed 18, this verifies the solution.
 

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Problem 2

Solve the following expression using LCM of 3 and 18: 5/3 + 1/18

Okay, lets begin

LCM(3,18)=18

5/3 = 30/18 , 1/18=1/18

Add the fractions:


30/18 + 1/18 = 31/18
 

Explanation

The sum of 5/3​ and 1/18​ is 31/18​, with, 18 as the common denominator.
 

Well explained 👍

Problem 3

Verify the prime factorization of LCM(3,10) using their prime factors.

Okay, lets begin

Prime factors of 3 =3 ,


Prime factors of 10= 2 × 5


LCM= 2 × 3 × 5= 30
 

Explanation

The LCM of 3 and 10 is 30, which is verified through the prime factorization.
 

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Problem 4

Simplify the expression: x/3 + 2/18 = 1

Okay, lets begin

LCM (3,18) =18

6x18 + 218 =1

6x + 2 = 18


  6x= 18–2


6x = 16


x=8/3
 

Explanation

The value of x is 8/3. This simplifies the original expression correctly using the LCM of 3 and 18. 

Well explained 👍

FAQs on LCM of 3 and 18

1.Is 945 a prime number?

 A prime number is the number that should have only two factors. As we know that 945 has more than 2 factors it's not a prime number, it is a composite number

2.Is 4 and 24 a factor pair of 96 ?

The pairs of 96 are (1,96), (2,48), (3,32), (4,24), (6,16)and(8,12).
 

3.What is the prime factorization of the 5005?

 The prime factors of 5005 are 5,7,11,13. Therefore, the products of prime factors are 5,7,11,13.
 

4.Is 34212 a multiple of 12?

34212 is when divided by 12 the quotient will be 2851 and the remainder will be zero. Hence, 34212 is the multiple of 2.
 

Important glossaries for LCM of 3 and 18

  • Co-prime: two numbers that have only one number that is 1 as their common factor.  For example, 8 and 15 are co prime numbers.
  • Even Number: A natural number is divisible by 2. For example, 2,4,68,10 etc.
  • Prime Factorization: The process of parting down a number into its prime factors is called Prime Factorization.  For example, prime factorization of 24 = 2 × 2 × 2 × 3.
     

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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.