LCM of 8 and 18
LCM of 8 and 18 is the smallest number among all common multiples of 8 and 18. The first few multiples of 8 and 18 are (8, 16, 24, 32, . . . ) and (18, 36, 54, 72, 90, 108, 126, . . . ) respectively. There are 3 commonly used methods to find LCM of 8 and 18 - by prime factorization, by division method, and by listing multiples.
1. | LCM of 8 and 18 |
2. | List of Methods |
3. | Solved Examples |
4. | FAQs |
What is the LCM of 8 and 18?
Answer: LCM of 8 and 18 is 72.
Explanation:
The LCM of two non-zero integers, x(8) and y(18), is the smallest positive integer m(72) that is divisible by both x(8) and y(18) without any remainder.
Methods to Find LCM of 8 and 18
Let's look at the different methods for finding the LCM of 8 and 18.
- By Prime Factorization Method
- By Division Method
- By Listing Multiples
LCM of 8 and 18 by Prime Factorization
Prime factorization of 8 and 18 is (2 × 2 × 2) = 23 and (2 × 3 × 3) = 21 × 32 respectively. LCM of 8 and 18 can be obtained by multiplying prime factors raised to their respective highest power, i.e. 23 × 32 = 72.
Hence, the LCM of 8 and 18 by prime factorization is 72.
LCM of 8 and 18 by Division Method
To calculate the LCM of 8 and 18 by the division method, we will divide the numbers(8, 18) by their prime factors (preferably common). The product of these divisors gives the LCM of 8 and 18.
- Step 1: Find the smallest prime number that is a factor of at least one of the numbers, 8 and 18. Write this prime number(2) on the left of the given numbers(8 and 18), separated as per the ladder arrangement.
- Step 2: If any of the given numbers (8, 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 8 and 18 is the product of all prime numbers on the left, i.e. LCM(8, 18) by division method = 2 × 2 × 2 × 3 × 3 = 72.
LCM of 8 and 18 by Listing Multiples
To calculate the LCM of 8 and 18 by listing out the common multiples, we can follow the given below steps:
- Step 1: List a few multiples of 8 (8, 16, 24, 32, . . . ) and 18 (18, 36, 54, 72, 90, 108, 126, . . . . )
- Step 2: The common multiples from the multiples of 8 and 18 are 72, 144, . . .
- Step 3: The smallest common multiple of 8 and 18 is 72.
∴ The least common multiple of 8 and 18 = 72.
☛ Also Check:
- LCM of 15 and 16 - 240
- LCM of 16 and 40 - 80
- LCM of 6, 8 and 9 - 72
- LCM of 70, 105 and 175 - 1050
- LCM of 48 and 64 - 192
- LCM of 3, 6, 9 and 12 - 36
- LCM of 12 and 30 - 60
LCM of 8 and 18 Examples
-
Example 1: Find the smallest number that is divisible by 8 and 18 exactly.
Solution:
The smallest number that is divisible by 8 and 18 exactly is their LCM.
⇒ Multiples of 8 and 18:- Multiples of 8 = 8, 16, 24, 32, 40, 48, 56, 64, 72, . . . .
- Multiples of 18 = 18, 36, 54, 72, 90, 108, 126, . . . .
Therefore, the LCM of 8 and 18 is 72.
-
Example 2: Verify the relationship between GCF and LCM of 8 and 18.
Solution:
The relation between GCF and LCM of 8 and 18 is given as,
LCM(8, 18) × GCF(8, 18) = Product of 8, 18
Prime factorization of 8 and 18 is given as, 8 = (2 × 2 × 2) = 23 and 18 = (2 × 3 × 3) = 21 × 32
LCM(8, 18) = 72
GCF(8, 18) = 2
LHS = LCM(8, 18) × GCF(8, 18) = 72 × 2 = 144
RHS = Product of 8, 18 = 8 × 18 = 144
⇒ LHS = RHS = 144
Hence, verified. -
Example 3: The product of two numbers is 144. If their GCD is 2, what is their LCM?
Solution:
Given: GCD = 2
product of numbers = 144
∵ LCM × GCD = product of numbers
⇒ LCM = Product/GCD = 144/2
Therefore, the LCM is 72.
The probable combination for the given case is LCM(8, 18) = 72.
FAQs on LCM of 8 and 18
What is the LCM of 8 and 18?
The LCM of 8 and 18 is 72. To find the least common multiple (LCM) of 8 and 18, we need to find the multiples of 8 and 18 (multiples of 8 = 8, 16, 24, 32 . . . . 72; multiples of 18 = 18, 36, 54, 72) and choose the smallest multiple that is exactly divisible by 8 and 18, i.e., 72.
Which of the following is the LCM of 8 and 18? 32, 24, 72, 21
The value of LCM of 8, 18 is the smallest common multiple of 8 and 18. The number satisfying the given condition is 72.
If the LCM of 18 and 8 is 72, Find its GCF.
LCM(18, 8) × GCF(18, 8) = 18 × 8
Since the LCM of 18 and 8 = 72
⇒ 72 × GCF(18, 8) = 144
Therefore, the greatest common factor = 144/72 = 2.
What are the Methods to Find LCM of 8 and 18?
The commonly used methods to find the LCM of 8 and 18 are:
- Listing Multiples
- Prime Factorization Method
- Division Method
What is the Least Perfect Square Divisible by 8 and 18?
The least number divisible by 8 and 18 = LCM(8, 18)
LCM of 8 and 18 = 2 × 2 × 2 × 3 × 3 [Incomplete pair(s): 2]
⇒ Least perfect square divisible by each 8 and 18 = LCM(8, 18) × 2 = 144 [Square root of 144 = √144 = ±12]
Therefore, 144 is the required number.
visual curriculum