How to find the Least Common Multiple of 18 and 28?
On this page below, we'll use the Prime Factorisation, and the List of Multiples method to find out the LCM of 18 and 28.
Follow the steps below, and let's calculate the LCM of 18 and 28.
Method 1 - Prime factorization
Step 1: Create a list of all the prime factors of the numbers 18 and 28:
Prime factors of 18
The prime factors of 18 are 2, 3 and 3. Prime factorization of 18 in exponential form is:
18 = 21x32
Prime factors of 28
The prime factors of 28 are 2, 2 and 7. Prime factorization of 28 in exponential form is:
28 = 22x71
Step 2: Identify the highest power of each prime number from the above boxes:
22, 32, 71
Step 3: Multiply these values together:
22x32x71=252
Step 4: The result:
As seen on the calculation above, we have now obtained the LCM of 18 and 28.
The Least Common Multiple of 18 and 28 is 252.
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 18:
18, 36, 54, 72, 90, 108, 126, 144, 162, 180, 198, 216, 234, 252, 270, 288, 306
Multiples of 28:
28, 56, 84, 112, 140, 168, 196, 224, 252, 280, 308, 336
Therefore,
LCM(18, 28) = 252