LCM of 18 and 40

LCM of 18 and 40 is the smallest number among all common multiples of 18 and 40. The first few multiples of 18 and 40 are (18, 36, 54, 72, 90, 108, 126, . . . ) and (40, 80, 120, 160, 200, . . . ) respectively. There are 3 commonly used methods to find LCM of 18 and 40 - by division method, by listing multiples, and by prime factorization.

Answer: LCM of 18 and 40 is 360.

Explanation:

The LCM of two non-zero integers, x(18) and y(40), is the smallest positive integer m(360) that is divisible by both x(18) and y(40) without any remainder.

The methods to find the LCM of 18 and 40 are explained below.

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

LCM of 18 and 40 by Listing Multiples

To calculate the LCM of 18 and 40 by listing out the common multiples, we can follow the given below steps:

• Step 1: List a few multiples of 18 (18, 36, 54, 72, 90, 108, 126, . . . ) and 40 (40, 80, 120, 160, 200, . . . . )
• Step 2: The common multiples from the multiples of 18 and 40 are 360, 720, . . .
• Step 3: The smallest common multiple of 18 and 40 is 360.

∴ The least common multiple of 18 and 40 = 360.

LCM of 18 and 40 by Prime Factorization

Prime factorization of 18 and 40 is (2 × 3 × 3) = 2¹ × 3² and (2 × 2 × 2 × 5) = 2³ × 5¹ respectively. LCM of 18 and 40 can be obtained by multiplying prime factors raised to their respective highest power, i.e. 2³ × 3² × 5¹ = 360.
Hence, the LCM of 18 and 40 by prime factorization is 360.

LCM of 18 and 40 by Division Method

To calculate the LCM of 18 and 40 by the division method, we will divide the numbers(18, 40) by their prime factors (preferably common). The product of these divisors gives the LCM of 18 and 40.

• Step 1: Find the smallest prime number that is a factor of at least one of the numbers, 18 and 40. Write this prime number(2) on the left of the given numbers(18 and 40), separated as per the ladder arrangement.
• Step 2: If any of the given numbers (18, 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 18 and 40 is the product of all prime numbers on the left, i.e. LCM(18, 40) by division method = 2 × 2 × 2 × 3 × 3 × 5 = 360.

☛ Also Check:

• LCM of 7, 8 and 9 - 504
• LCM of 2, 4 and 8 - 8
• LCM of 2, 5 and 6 - 30
• LCM of 4 and 18 - 36
• LCM of 16, 24 and 36 - 144
• LCM of 21 and 22 - 462
• LCM of 80, 85 and 90 - 12240

FAQs on LCM of 18 and 40

What is the LCM of 18 and 40?

The LCM of 18 and 40 is 360. To find the least common multiple (LCM) of 18 and 40, we need to find the multiples of 18 and 40 (multiples of 18 = 18, 36, 54, 72 . . . . 360; multiples of 40 = 40, 80, 120, 160 . . . . 360) and choose the smallest multiple that is exactly divisible by 18 and 40, i.e., 360.

What are the Methods to Find LCM of 18 and 40?

The commonly used methods to find the LCM of 18 and 40 are:

• Listing Multiples
• Division Method
• Prime Factorization Method

What is the Relation Between GCF and LCM of 18, 40?

The following equation can be used to express the relation between GCF and LCM of 18 and 40, i.e. GCF × LCM = 18 × 40.

What is the Least Perfect Square Divisible by 18 and 40?

The least number divisible by 18 and 40 = LCM(18, 40)
LCM of 18 and 40 = 2 × 2 × 2 × 3 × 3 × 5 [Incomplete pair(s): 2, 5]
⇒ Least perfect square divisible by each 18 and 40 = LCM(18, 40) × 2 × 5 = 3600 [Square root of 3600 = √3600 = ±60]
Therefore, 3600 is the required number.

If the LCM of 40 and 18 is 360, Find its GCF.

LCM(40, 18) × GCF(40, 18) = 40 × 18
Since the LCM of 40 and 18 = 360
⇒ 360 × GCF(40, 18) = 720
Therefore, the GCF (greatest common factor) = 720/360 = 2.