LCM of 4 and 18
LCM of 4 and 18 is the smallest number among all common multiples of 4 and 18. The first few multiples of 4 and 18 are (4, 8, 12, 16, 20, . . . ) and (18, 36, 54, 72, 90, 108, . . . ) respectively. There are 3 commonly used methods to find LCM of 4 and 18 - by prime factorization, by division method, and by listing multiples.
1. | LCM of 4 and 18 |
2. | List of Methods |
3. | Solved Examples |
4. | FAQs |
What is the LCM of 4 and 18?
Answer: LCM of 4 and 18 is 36.
Explanation:
The LCM of two non-zero integers, x(4) and y(18), is the smallest positive integer m(36) that is divisible by both x(4) and y(18) without any remainder.
Methods to Find LCM of 4 and 18
The methods to find the LCM of 4 and 18 are explained below.
- By Prime Factorization Method
- By Listing Multiples
- By Division Method
LCM of 4 and 18 by Prime Factorization
Prime factorization of 4 and 18 is (2 × 2) = 22 and (2 × 3 × 3) = 21 × 32 respectively. LCM of 4 and 18 can be obtained by multiplying prime factors raised to their respective highest power, i.e. 22 × 32 = 36.
Hence, the LCM of 4 and 18 by prime factorization is 36.
LCM of 4 and 18 by Listing Multiples
To calculate the LCM of 4 and 18 by listing out the common multiples, we can follow the given below steps:
- Step 1: List a few multiples of 4 (4, 8, 12, 16, 20, . . . ) and 18 (18, 36, 54, 72, 90, 108, . . . . )
- Step 2: The common multiples from the multiples of 4 and 18 are 36, 72, . . .
- Step 3: The smallest common multiple of 4 and 18 is 36.
∴ The least common multiple of 4 and 18 = 36.
LCM of 4 and 18 by Division Method
To calculate the LCM of 4 and 18 by the division method, we will divide the numbers(4, 18) by their prime factors (preferably common). The product of these divisors gives the LCM of 4 and 18.
- Step 1: Find the smallest prime number that is a factor of at least one of the numbers, 4 and 18. Write this prime number(2) on the left of the given numbers(4 and 18), separated as per the ladder arrangement.
- Step 2: If any of the given numbers (4, 18) is a multiple of 2, divide it by 2 and write the quotient below it. Bring down any number that is not divisible by the prime number.
- Step 3: Continue the steps until only 1s are left in the last row.
The LCM of 4 and 18 is the product of all prime numbers on the left, i.e. LCM(4, 18) by division method = 2 × 2 × 3 × 3 = 36.
☛ Also Check:
- LCM of 7 and 21 - 21
- LCM of 3, 6 and 7 - 42
- LCM of 4, 9 and 10 - 180
- LCM of 14 and 122 - 854
- LCM of 4, 6 and 12 - 12
- LCM of 7 and 35 - 35
- LCM of 30, 72 and 432 - 2160
LCM of 4 and 18 Examples
-
Example 1: The product of two numbers is 72. If their GCD is 2, what is their LCM?
Solution:
Given: GCD = 2
product of numbers = 72
∵ LCM × GCD = product of numbers
⇒ LCM = Product/GCD = 72/2
Therefore, the LCM is 36.
The probable combination for the given case is LCM(4, 18) = 36. -
Example 2: The GCD and LCM of two numbers are 2 and 36 respectively. If one number is 4, find the other number.
Solution:
Let the other number be a.
∵ GCD × LCM = 4 × a
⇒ a = (GCD × LCM)/4
⇒ a = (2 × 36)/4
⇒ a = 18
Therefore, the other number is 18. -
Example 3: Verify the relationship between GCF and LCM of 4 and 18.
Solution:
The relation between GCF and LCM of 4 and 18 is given as,
LCM(4, 18) × GCF(4, 18) = Product of 4, 18
Prime factorization of 4 and 18 is given as, 4 = (2 × 2) = 22 and 18 = (2 × 3 × 3) = 21 × 32
LCM(4, 18) = 36
GCF(4, 18) = 2
LHS = LCM(4, 18) × GCF(4, 18) = 36 × 2 = 72
RHS = Product of 4, 18 = 4 × 18 = 72
⇒ LHS = RHS = 72
Hence, verified.
FAQs on LCM of 4 and 18
What is the LCM of 4 and 18?
The LCM of 4 and 18 is 36. To find the LCM (least common multiple) of 4 and 18, we need to find the multiples of 4 and 18 (multiples of 4 = 4, 8, 12, 16 . . . . 36; multiples of 18 = 18, 36, 54, 72) and choose the smallest multiple that is exactly divisible by 4 and 18, i.e., 36.
What are the Methods to Find LCM of 4 and 18?
The commonly used methods to find the LCM of 4 and 18 are:
- Prime Factorization Method
- Listing Multiples
- Division Method
If the LCM of 18 and 4 is 36, Find its GCF.
LCM(18, 4) × GCF(18, 4) = 18 × 4
Since the LCM of 18 and 4 = 36
⇒ 36 × GCF(18, 4) = 72
Therefore, the GCF = 72/36 = 2.
Which of the following is the LCM of 4 and 18? 45, 36, 42, 2
The value of LCM of 4, 18 is the smallest common multiple of 4 and 18. The number satisfying the given condition is 36.
How to Find the LCM of 4 and 18 by Prime Factorization?
To find the LCM of 4 and 18 using prime factorization, we will find the prime factors, (4 = 2 × 2) and (18 = 2 × 3 × 3). LCM of 4 and 18 is the product of prime factors raised to their respective highest exponent among the numbers 4 and 18.
⇒ LCM of 4, 18 = 22 × 32 = 36.
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