LCM of 20 and 40

LCM of 20 and 40 is the smallest number among all common multiples of 20 and 40. The first few multiples of 20 and 40 are (20, 40, 60, 80, 100, . . . ) and (40, 80, 120, 160, . . . ) respectively. There are 3 commonly used methods to find LCM of 20 and 40 - by listing multiples, by division method, and by prime factorization.

Answer: LCM of 20 and 40 is 40.

Explanation:

The LCM of two non-zero integers, x(20) and y(40), is the smallest positive integer m(40) that is divisible by both x(20) and y(40) without any remainder.

The methods to find the LCM of 20 and 40 are explained below.

• By Prime Factorization Method
• By Listing Multiples
• By Division Method

LCM of 20 and 40 by Prime Factorization

Prime factorization of 20 and 40 is (2 × 2 × 5) = 2² × 5¹ and (2 × 2 × 2 × 5) = 2³ × 5¹ respectively. LCM of 20 and 40 can be obtained by multiplying prime factors raised to their respective highest power, i.e. 2³ × 5¹ = 40.
Hence, the LCM of 20 and 40 by prime factorization is 40.

LCM of 20 and 40 by Listing Multiples

To calculate the LCM of 20 and 40 by listing out the common multiples, we can follow the given below steps:

• Step 1: List a few multiples of 20 (20, 40, 60, 80, 100, . . . ) and 40 (40, 80, 120, 160, . . . . )
• Step 2: The common multiples from the multiples of 20 and 40 are 40, 80, . . .
• Step 3: The smallest common multiple of 20 and 40 is 40.

∴ The least common multiple of 20 and 40 = 40.

LCM of 20 and 40 by Division Method

To calculate the LCM of 20 and 40 by the division method, we will divide the numbers(20, 40) by their prime factors (preferably common). The product of these divisors gives the LCM of 20 and 40.

• Step 1: Find the smallest prime number that is a factor of at least one of the numbers, 20 and 40. Write this prime number(2) on the left of the given numbers(20 and 40), separated as per the ladder arrangement.
• Step 2: If any of the given numbers (20, 40) 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 20 and 40 is the product of all prime numbers on the left, i.e. LCM(20, 40) by division method = 2 × 2 × 2 × 5 = 40.

☛ Also Check:

• LCM of 8 and 16 - 16
• LCM of 8, 16 and 24 - 48
• LCM of 14 and 35 - 70
• LCM of 207 and 138 - 414
• LCM of 10, 15 and 20 - 60
• LCM of 28 and 32 - 224
• LCM of 4, 6 and 8 - 24

FAQs on LCM of 20 and 40

What is the LCM of 20 and 40?

The LCM of 20 and 40 is 40. To find the LCM (least common multiple) of 20 and 40, we need to find the multiples of 20 and 40 (multiples of 20 = 20, 40, 60, 80; multiples of 40 = 40, 80, 120, 160) and choose the smallest multiple that is exactly divisible by 20 and 40, i.e., 40.

What are the Methods to Find LCM of 20 and 40?

The commonly used methods to find the LCM of 20 and 40 are:

• Division Method
• Listing Multiples
• Prime Factorization Method

If the LCM of 40 and 20 is 40, Find its GCF.

LCM(40, 20) × GCF(40, 20) = 40 × 20
Since the LCM of 40 and 20 = 40
⇒ 40 × GCF(40, 20) = 800
Therefore, the greatest common factor = 800/40 = 20.

What is the Least Perfect Square Divisible by 20 and 40?

The least number divisible by 20 and 40 = LCM(20, 40)
LCM of 20 and 40 = 2 × 2 × 2 × 5 [Incomplete pair(s): 2, 5]
⇒ Least perfect square divisible by each 20 and 40 = LCM(20, 40) × 2 × 5 = 400 [Square root of 400 = √400 = ±20]
Therefore, 400 is the required number.

What is the Relation Between GCF and LCM of 20, 40?

The following equation can be used to express the relation between GCF and LCM of 20 and 40, i.e. GCF × LCM = 20 × 40.