LCM of 7 and 15
Reviewed By : Phani Ponnapalli
Last Updated at : Mar 29,2023
It is easy to find the LCM of 7 and 15 with the help of the handy LCM Calculator. You have to enter 44, and 60 as inputs to avail the LCM 105 as output. Here you can check the answer for Find the LCM of 7 and 15.
What is LCM of 7 and 15
Given Numbers are 7, 15
We can find the LCM of 7, 15 using the brute force method, prime factorization method, or GCD method.
To use brute force method, list the multiples of 7 and 15
Multiples of 7 =7,14,21,28,35,42,49,56,63,70,77,84,91,98,105,112,119,
Multiples of 15 =15,30,45,60,75,90,105,120,135,150,165,180,195,210,225,240,255,
Now, get the least common multiple of 7, 15 which is 105
So, the LCM of 7, 15 is 105.
Least Common Multiple (LCM) of 7 and 15 with the help of Prime Factorisation
One method for determining the LCM of 7 and 15 is to compare the prime factorization of each number. You can find the prime factorization for each number by following the instructions below:
Here is 7's prime factorization:
| 7 | 7 |
| 1 |
Prime factors of 7 are 7.
7 = 71
And this is 15's prime factorization:
| 3 | 15 |
| 5 | 5 |
| 1 |
Prime factors of 15 are 3,5.
15 = 31×51
When comparing the prime factorization of these two numbers, look for the highest power to which each prime factor is raised. In this case, the following primary factors must be considered:7, 3,5
.31×51×71 = 105
This shows that the LCM of 7 and 15 is 105.
How to Calculate the LCM of 7 and 15 Using Common Multiples
The first step in determining the Least Common Multiple of 7 and 15 is to generate a list of multiples for each number.
Lets look at the multiples of these two numbers, 7 and 15:
Lets look at the first ten multiples of these numbers, 7 and 15:
7,14,21,28,35,42,49,56,63,119 are the first ten multiples of 7.
15,30,45,60,75,90,105,120,135,255 are the first ten multiples of 15.
You can continue to list the multiples of these numbers until you find a match. Once you have found a match, or several matches, the Least Common Multiple is the smallest of these matches. The first matching multiple(s) of 7 and 15, for example, are 84, 119, and 240. 105 is the least common multiple since it is the smallest.
7 and 15 have an LCM of 105.
Least Common Multiple of 7 and 15 with GCF Formula
The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 7 and 15, than apply into the LCM equation.
GCF(7,15) = 1
LCM(7,15) = ( 7 × 15) / 1
LCM(7,15) = 105 / 1
LCM(7,15) = 105
Related Least Common Multiples of 7
Related Least Common Multiples of 15
Frequently Asked Questions on LCM of 7 and 15
1. What is the LCM of 7 and 15?
The LCM of 7 and 15 is 105.
2. How to find the lowest common multiple of 7 and 15?
To find the lowest common multiple of 7 and 15, we have to get the multip;es of both numbers and identify the least common multiple in them which is 105.
3. What are the Factors of 7?
Answer: Factors of 7 are 1, 7. There are 2 integers that are factors of 7. The greatest factor of 7 is 7.
4. What are the Factors of 15?
Answer: Factors of 15 are 1, 3, 5, 15. There are 4 integers that are factors of 15. The greatest factor of 15 is 15.
5. How to Find the LCM of 7 and 15?Answer:
Least Common Multiple of 7 and 15 = 105
Step 1: Find the prime factorization of 7
7 = 7
Step 2: Find the prime factorization of 15
15 = 3 x 5
Step 3: Multiply each factor the greater number of times it occurs in steps i) or ii) above to find the lcm:
LCM = 105 = 3 x 5 x 7
Step 4: Therefore, the least common multiple of 7 and 15 is 105.