What is the LCM of 15 and 21?
The least common multiple can be defined as the lowest positive integer that is a multiple of every number in a given set of numbers.
Answer: LCM of 15 and 21 is 105
Lets see how to find the LCM of 15 and 21
We will be calculating the LCM in two ways:
- Prime factorization
- Using Formula
LCM of 15 and 21 using Prime Factorization:
We will be prime factorising the numbers 15 and 21 as shown below
LCM by using formula:
LCM (a, b) = (a × b) / GCF (a, b)
The Greatest Common Factor of (15,21) = 3
Therefore by substituting we get,
LCM of 15 and 21 = (15 × 21) / 3
LCM of 15 and 21 = 105