What is LCM ? Example of How to Find LCM?

LCM, also known as the Least Common Multiple of given numbers, is defined as the smallest possible number, which is divisible exactly by the given numbers. LCM can be calculated for two or more numbers or fractions too. There are various ways to find the LCM, such as the listing multiples method, division method, and by formula. We will be seeing below a few examples to see how these methods work.

Before proceeding towards learning the concepts of HCF and LCM, students should be well-practiced on the basic arithmetic operations with numbers as well as finding multiples of numbers, their factors, etc., so as to make the calculations involved easier to understand.

Suppose we have to calculate the LCM of the numbers 4 and 5. Let us use the listing method here to find the LCM of 4 and 5.

Firstly, we will list down the multiples of 4 and 5 as below:

  • Listing multiples of 4 : 4, 8, 12, 16, 20, 24, 28
  • Listing multiples of 5 : 5, 10, 15, 20, 25, 30

We can see that the common multiple here is 20, which is hence the LCM of 4 and 5.

Now, let us see how to find the LCM of 4 and 5, with the help of the formula:

The formula we will be using is LCM(a,b) = ( a × b) / GCF (a,b)

The Greatest Common Factor (GCF) of numbers 4 and 5 is = 1


LCM of 4 and 5 = (4 × 5)/1 = 20/1 = 20

LCM of 4 and 5 = 20

So we see that the solution to our question LCM of 4 and 5 is the same.

Hence we see that though the concept and calculations are simple to understand, still, the students would require more consistent practice to get used to the calculations involving different numbers. Math can only be leveled up through regular practice, and math worksheets hence play a very important role in the reinforcement of the concepts learned while enhancing their analytical and problem-solving skills.

These days with plenty of educational resources available online, math worksheets are also very easily available on the internet for free. Cuemath is one such online education brand that has LCM worksheets for students of all grades. These worksheets have fun and visual elements to keep the children engaged throughout the process of learning. LCM concept is used in higher math, too; hence these worksheets will provide an in-depth approach with the variety of questions and also the self-explanatory answer keys provided, which means they have step-by-step solutions. This will not only help the kids check their answers but also will give them a proper approach and strategy towards problem-solving by following the steps in the answer key.

Practicing LCM worksheets will also present the essential tips and tricks, which will help the students in quicker calculations and enhance their mental math skills too. Apart from these LCM worksheets, students can also practice the ‘Factor worksheets’. Understanding factors is important as it has further usage in finding the LCM and HCF of numbers and advanced math concepts.

The factors worksheet will help the students in gaining an understanding of the factorization pattern for different kinds of numbers. These worksheets have several questions to practice ranging from the easy ones to little complex ones which will make the math practice session easy to follow. They will gain an insight into the prime factorization and prime numbers also. Students will also gain a sense of confidence when faced with math problems in their exams.