LCM of 40 and 80
LCM of 40 and 80 is the smallest number among all common multiples of 40 and 80. The first few multiples of 40 and 80 are (40, 80, 120, 160, . . . ) and (80, 160, 240, 320, . . . ) respectively. There are 3 commonly used methods to find LCM of 40 and 80  by division method, by prime factorization, and by listing multiples.
1.  LCM of 40 and 80 
2.  List of Methods 
3.  Solved Examples 
4.  FAQs 
What is the LCM of 40 and 80?
Answer: LCM of 40 and 80 is 80.
Explanation:
The LCM of two nonzero integers, x(40) and y(80), is the smallest positive integer m(80) that is divisible by both x(40) and y(80) without any remainder.
Methods to Find LCM of 40 and 80
The methods to find the LCM of 40 and 80 are explained below.
 By Prime Factorization Method
 By Listing Multiples
 By Division Method
LCM of 40 and 80 by Prime Factorization
Prime factorization of 40 and 80 is (2 × 2 × 2 × 5) = 2^{3} × 5^{1} and (2 × 2 × 2 × 2 × 5) = 2^{4} × 5^{1} respectively. LCM of 40 and 80 can be obtained by multiplying prime factors raised to their respective highest power, i.e. 2^{4} × 5^{1} = 80.
Hence, the LCM of 40 and 80 by prime factorization is 80.
LCM of 40 and 80 by Listing Multiples
To calculate the LCM of 40 and 80 by listing out the common multiples, we can follow the given below steps:
 Step 1: List a few multiples of 40 (40, 80, 120, 160, . . . ) and 80 (80, 160, 240, 320, . . . . )
 Step 2: The common multiples from the multiples of 40 and 80 are 80, 160, . . .
 Step 3: The smallest common multiple of 40 and 80 is 80.
∴ The least common multiple of 40 and 80 = 80.
LCM of 40 and 80 by Division Method
To calculate the LCM of 40 and 80 by the division method, we will divide the numbers(40, 80) by their prime factors (preferably common). The product of these divisors gives the LCM of 40 and 80.
 Step 1: Find the smallest prime number that is a factor of at least one of the numbers, 40 and 80. Write this prime number(2) on the left of the given numbers(40 and 80), separated as per the ladder arrangement.
 Step 2: If any of the given numbers (40, 80) 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 40 and 80 is the product of all prime numbers on the left, i.e. LCM(40, 80) by division method = 2 × 2 × 2 × 2 × 5 = 80.
☛ Also Check:
 LCM of 4, 6 and 10  60
 LCM of 5 and 9  45
 LCM of 30, 36 and 40  360
 LCM of 4, 12, 16 and 24  48
 LCM of 12, 16 and 24  48
 LCM of 2, 3, 4 and 5  60
 LCM of 5 and 8  40
LCM of 40 and 80 Examples

Example 1: The product of two numbers is 3200. If their GCD is 40, what is their LCM?
Solution:
Given: GCD = 40
product of numbers = 3200
∵ LCM × GCD = product of numbers
⇒ LCM = Product/GCD = 3200/40
Therefore, the LCM is 80.
The probable combination for the given case is LCM(40, 80) = 80. 
Example 2: The GCD and LCM of two numbers are 40 and 80 respectively. If one number is 80, find the other number.
Solution:
Let the other number be p.
∵ GCD × LCM = 80 × p
⇒ p = (GCD × LCM)/80
⇒ p = (40 × 80)/80
⇒ p = 40
Therefore, the other number is 40. 
Example 3: Find the smallest number that is divisible by 40 and 80 exactly.
Solution:
The smallest number that is divisible by 40 and 80 exactly is their LCM.
⇒ Multiples of 40 and 80: Multiples of 40 = 40, 80, 120, 160, 200, 240, 280, . . . .
 Multiples of 80 = 80, 160, 240, 320, 400, 480, 560, . . . .
Therefore, the LCM of 40 and 80 is 80.
FAQs on LCM of 40 and 80
What is the LCM of 40 and 80?
The LCM of 40 and 80 is 80. To find the least common multiple of 40 and 80, we need to find the multiples of 40 and 80 (multiples of 40 = 40, 80, 120, 160; multiples of 80 = 80, 160, 240, 320) and choose the smallest multiple that is exactly divisible by 40 and 80, i.e., 80.
If the LCM of 80 and 40 is 80, Find its GCF.
LCM(80, 40) × GCF(80, 40) = 80 × 40
Since the LCM of 80 and 40 = 80
⇒ 80 × GCF(80, 40) = 3200
Therefore, the GCF = 3200/80 = 40.
How to Find the LCM of 40 and 80 by Prime Factorization?
To find the LCM of 40 and 80 using prime factorization, we will find the prime factors, (40 = 2 × 2 × 2 × 5) and (80 = 2 × 2 × 2 × 2 × 5). LCM of 40 and 80 is the product of prime factors raised to their respective highest exponent among the numbers 40 and 80.
⇒ LCM of 40, 80 = 2^{4} × 5^{1} = 80.
Which of the following is the LCM of 40 and 80? 12, 35, 25, 80
The value of LCM of 40, 80 is the smallest common multiple of 40 and 80. The number satisfying the given condition is 80.
What is the Least Perfect Square Divisible by 40 and 80?
The least number divisible by 40 and 80 = LCM(40, 80)
LCM of 40 and 80 = 2 × 2 × 2 × 2 × 5 [Incomplete pair(s): 5]
⇒ Least perfect square divisible by each 40 and 80 = LCM(40, 80) × 5 = 400 [Square root of 400 = √400 = ±20]
Therefore, 400 is the required number.
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