LCM Of 4 And 18

The LCM or the least common multiple of 2 numbers is the smallest number that appears as a multiple of both numbers. In case of 4 and 18, The LCM is 36. But how did we get to this answer? There are different ways to obtain a LCM of 2 or more numbers. Let us take a look at those methods.
 

Remember that we previously said there are plenty of ways to calculate the LCM of two numbers or more. Then some of those methods make it extremely easy for us to find the LCM of any two numbers. Those methods are: 

• Listing of Multiples

• Prime Factorization

• Division Method

Finally, now we will learn how each of these methods can help us to calculate LCM of given numbers.
 

This method will help us find the LCM of the numbers by listing the multiples of the given numbers. Let us take a step by step look at this method.

The first step is to list all the multiples of the given numbers. 

Multiples Of 4: 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 68, 72, 76, 80.

Multiples Of 18: 18, 36, 54, 72, 90, 108, 126, 144, 162, and 180.

The second step is to find the smallest common multiples in both the numbers. In this case, that number is 36 as highlighted above.

By this way we will be able to tell the LCM of given numbers.
 

Let us break down the process of prime factorization into steps and make it easy for children to understand.
The first step is to break down the given numbers into its primal form. The primal form of the number is:

4= 2×2

18= 3×3×2

As you can see, 2 appears as a prime factor in both numbers. So instead of considering 2 three times, we will only consider it twice. So the final equation will look like (3×3×2×2).

So after the multiplication, we will be getting the LCM as 36.

As you can see, using this method can be easier for larger numbers compared to the previous method. 
 

The method to calculate the LCM is really simple. We’ll break these given numbers apart till it comes down to one, by dividing it by the prime factors. The product of the divisors that will come is the LCM of the given numbers.

Let us understand it step by step:

• The first thing is to find the number common in both the numbers. Here it is 2. In that case, we divide both the numbers by 2. It will reduce the values of the numbers to 2 and 9.

• 2 is a prime number, it can be divided by only 2. That means 9 is left by dividing that.

• 3 is a factor of 9 and 9 can be divided by 3. Then, we will have 3. That being said, we’ll end up dividing by 3 again and only have one in the last row.

• This is the end of division. However, we will now find the product of the numbers on the left. The numbers on the left side are: 2,2,3 and 3. 

These numbers multiplied give 36. On this basis, therefore, the LCM of the 4 and 18 becomes 36.
 

• Least Common Multiple (LCM): That smallest number of numbers that two or more numbers can share as a multiple. For example, the LCM of 4 and 18 is 36.

• Prime Number: A number that is more than 1, has no divisors other than 1 and itself. The four are 2, 3, 5 and 7.

• GCF (Greatest Common Factor): The largest number divisible by two or more numbers. The GCF of 4 and 18 is 2 for example.

• Prime Factorization: Reducing a number down to its prime factors. The example of prime factorization 18= 2 × 3 × 3 or 2 × 3².