LCM of 15 and 18 is 90. This article is designed by experts in a simple to understand language to make the learning process easier. Learning the LCM concept in a detailed manner helps students to simplify any problem effortlessly. Students can make use of HCF and LCM to learn about how to represent the HCF and LCM of given numbers using the prime factorisation and division method in an efficient manner. Let us discuss how to find the least common multiple of 15 and 18 with a complete explanation in this article.
What is LCM of 15 and 18?
The answer to this question is 90.
How to Find LCM of 15 and 18?
We can use the following methods to find the LCM of 15 and 18 with ease:
- Prime Factorisation
- Division method
- Listing the multiples
LCM of 15 and 18 Using Prime Factorisation Method
By prime factorisation method, we can write 15 and 48 as the product of prime numbers, such that;
15 = 3 × 5
18 = 2 × 3 × 3
LCM (15, 18) = 2 × 3 × 3 × 5 = 90
LCM of 15 and 18 Using Division Method
Here, we divide the numbers 15 and 18 by their prime factors to find their LCM. The product of these divisors represents the least common multiple of 15 and 18.
2 | 15 | 18 |
3 | 15 | 9 |
3 | 5 | 3 |
5 | 5 | 1 |
x | 1 | 1 |
No more further division can be done.
Hence, LCM (15, 18) = 2 × 3 × 3 × 5 = 90
LCM of 15 and 18 Using Listing the Multiples
To calculate the least common multiple of 15 and 18 using listing multiples, we list out the multiples of 15 and 18 as shown below.
Multiples of 15 | Multiples of 18 |
15 | 18 |
30 | 36 |
45 | 54 |
60 | 72 |
75 | 90 |
90 | 108 |
105 | 126 |
LCM (15, 18) = 90
Related Articles
Prime Factorisation and Division Method for LCM and HCF
Video Lesson on Applications of LCM
Solved Examples
Q. 1:What is the smallest number that is divisible by both 15 and 18?
Solution: 90 is the smallest number that is divisible by both 15 and 18.
Q. 2:What is the LCM of 1, 15 and 18?
Solution: The LCM of 1, 15 and 18 is 90.
Frequently Asked Questions on LCM of 15 and 18
Q1
Write the LCM of 15 and 18.
The LCM of 15 and 18 is 90.
Q2
Is the LCM of 15 and 18 the same as the HCF of 15 and 18?
No. The LCM of 15 and 18 is 90 and the HCF of 15 and 18 is 3.
Q3
What are the common prime factors of 15 and 18?
3 is the only common prime factor of 15 and 18.
