Least Common Multiple  of 5 and 18 is 90

How to find the Least Common Multiple of 5 and 18?

On this page below, we'll use the Prime Factorisation, and the List of Multiples method to find out the LCM of 5 and 18.

Follow the steps below, and let's calculate the LCM of 5 and 18.


Method 1 - Prime factorization

Step 1: Create a list of all the prime factors of the numbers 5 and 18:

Prime factors of 5

The prime factors of 5 are 5. Prime factorization of 5 in exponential form is:

5 = 51

Prime factors of 18

The prime factors of 18 are 2, 3 and 3. Prime factorization of 18 in exponential form is:

18 = 21x32


Step 2: Identify the highest power of each prime number from the above boxes:

51, 21, 32


Step 3: Multiply these values together:

51x21x32=90


Step 4: The result:

As seen on the calculation above, we have now obtained the LCM of 5 and 18.

The Least Common Multiple of 5 and 18 is 90.


Method 2 - List of Multiples

Find and list multiples of each number until the first common multiple is found. This is the lowest common multiple.


Multiples of 5:

5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105

Multiples of 18:

18, 36, 54, 72, 90, 108, 126, 144


Therefore,

LCM(5, 18) = 90