LCM of 7 and 20 is 140. LCM is the smallest common multiple of two or more numbers. Learn the simple method of finding the least common factor by referring to the article prepared by experts with care for students. Using the article Least Common Multiple (LCM), students get all the minute details regarding the LCM concept. In this article, let us learn the simple way of representing the least common multiple of 7 and 20.
What is LCM of 7 and 20?
The Least Common Multiple of 7 and 20 is 140.
How to Find LCM of 7 and 20?
The LCM of 7 and 20 can be determined by using three methods:
- Prime Factorisation
- Division method
- Listing the Multiples
LCM of 7 and 20 Using Prime Factorisation Method
In the Prime Factorisation method, the numbers can be expressed as the product of prime numbers. Here, 7 and 20 can be represented as;
7 = 7
20 = 2 × 2 × 5
LCM (7, 20) = 2 × 2 × 5 × 7 = 140
LCM of 7 and 20 Using Division Method
In the division method, we divide the numbers 7 and 20 by their prime factors until we get the result as one in the complete row. The product of these divisors gives the least common multiple of 7 and 20.
| 2 | 7 | 20 |
| 2 | 7 | 10 |
| 5 | 7 | 5 |
| 7 | 7 | 1 |
| x | 1 | 1 |
No further division can be done.
Therefore, LCM (7, 20) = 2 × 2 × 5 × 7 = 140
LCM of 7 and 20 Using Listing the Multiples
Here, we list down the multiples of given natural numbers to find the lowest common multiple among them. A few multiples of 7 and 20 are as follows:
Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, ………,126, 133, 140,…………
Multiples of 20: 20, 40, 60, 80, 100, 120, 140,………….
LCM (7, 20) = 140
Related Articles
Prime Factorization and Division Method for LCM and HCF
Video Lesson on Applications of LCM
Solved Examples
1. What is the smallest number that is divisible by both 7 and 20?
Solution: 140 is the smallest number that is divisible by both 7 and 20.
2. The GCD and LCM of the two numbers are 1 and 140. If one number is 20, what is the other number?
Solution: Let the other number be k
We know that,
GCD × LCM = 20 × k
k = (GCD × LCM) / 20
k = (1 × 140) / 20
k = 7
Hence the other number is 7.
Frequently Asked Questions on LCM of 7 and 20
What is the LCM of 7 and 20?
What are the methods used to find the LCM of 7 and 20?
The following methods are used to find the LCM of 7 and 20
Prime Factorisation
Division Method
Listing the Multiples
Is 150 the LCM of 7 and 20?
Mention the LCM of 7 and 20 and the HCF of 7 and 20.
What is the GCF if the LCM of 7 and 20 is 140?
GCF × LCM = 7 × 20
Given
LCM = 140
GCF × 140 = 7 × 20
GCF = 1
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