The smallest number that can be divided by the given numbers without leaving any remainder is called the LCM.
LCM by Prime factorisation method:
In this method, we first list the prime factors of the numbers and then multiply the common factors and the remaining prime factors.
Example : Find the LCM of 18 and 24.
Prime factorisation of 18 :
Prime factorisation of 24 :
LCM by Common Division method :
Step 1: Divide by the smallest prime number which can divide at least one of the numbers and bring down the numbers that cannot be divided further.
Step 2 : Continue division by the smallest possible prime numbers till the last row contains prime numbers or co-prime numbers.
Step 3 : Multiple all the factors and the numbers in the last row get LCM.
For example : Find the LCM of 12,16, 20.