LCM of 7 and 8

LCM of 7 and 8 is the smallest number among all common multiples of 7 and 8. The first few multiples of 7 and 8 are (7, 14, 21, 28, . . . ) and (8, 16, 24, 32, 40, 48, 56, . . . ) respectively. There are 3 commonly used methods to find LCM of 7 and 8 - by listing multiples, by prime factorization, and by division method.

Answer: LCM of 7 and 8 is 56.

Explanation:

The LCM of two non-zero integers, x(7) and y(8), is the smallest positive integer m(56) that is divisible by both x(7) and y(8) without any remainder.

Let's look at the different methods for finding the LCM of 7 and 8.

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

LCM of 7 and 8 by Prime Factorization

Prime factorization of 7 and 8 is (7) = 7¹ and (2 × 2 × 2) = 2³ respectively. LCM of 7 and 8 can be obtained by multiplying prime factors raised to their respective highest power, i.e. 2³ × 7¹ = 56.
Hence, the LCM of 7 and 8 by prime factorization is 56.

LCM of 7 and 8 by Division Method

To calculate the LCM of 7 and 8 by the division method, we will divide the numbers(7, 8) by their prime factors (preferably common). The product of these divisors gives the LCM of 7 and 8.

• Step 1: Find the smallest prime number that is a factor of at least one of the numbers, 7 and 8. Write this prime number(2) on the left of the given numbers(7 and 8), separated as per the ladder arrangement.
• Step 2: If any of the given numbers (7, 8) 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 7 and 8 is the product of all prime numbers on the left, i.e. LCM(7, 8) by division method = 2 × 2 × 2 × 7 = 56.

LCM of 7 and 8 by Listing Multiples

To calculate the LCM of 7 and 8 by listing out the common multiples, we can follow the given below steps:

• Step 1: List a few multiples of 7 (7, 14, 21, 28, . . . ) and 8 (8, 16, 24, 32, 40, 48, 56, . . . . )
• Step 2: The common multiples from the multiples of 7 and 8 are 56, 112, . . .
• Step 3: The smallest common multiple of 7 and 8 is 56.

∴ The least common multiple of 7 and 8 = 56.

☛ Also Check:

• LCM of 10 and 12 - 60
• LCM of 18 and 45 - 90
• LCM of 20, 25 and 30 - 300
• LCM of 30 and 35 - 210
• LCM of 28 and 30 - 420
• LCM of 3, 4 and 7 - 84
• LCM of 7 and 11 - 77

FAQs on LCM of 7 and 8

What is the LCM of 7 and 8?

The LCM of 7 and 8 is 56. To find the LCM of 7 and 8, we need to find the multiples of 7 and 8 (multiples of 7 = 7, 14, 21, 28 . . . . 56; multiples of 8 = 8, 16, 24, 32 . . . . 56) and choose the smallest multiple that is exactly divisible by 7 and 8, i.e., 56.

What is the Least Perfect Square Divisible by 7 and 8?

The least number divisible by 7 and 8 = LCM(7, 8)
LCM of 7 and 8 = 2 × 2 × 2 × 7 [Incomplete pair(s): 2, 7]
⇒ Least perfect square divisible by each 7 and 8 = LCM(7, 8) × 2 × 7 = 784 [Square root of 784 = √784 = ±28]
Therefore, 784 is the required number.

What is the Relation Between GCF and LCM of 7, 8?

The following equation can be used to express the relation between GCF and LCM of 7 and 8, i.e. GCF × LCM = 7 × 8.

If the LCM of 8 and 7 is 56, Find its GCF.

LCM(8, 7) × GCF(8, 7) = 8 × 7
Since the LCM of 8 and 7 = 56
⇒ 56 × GCF(8, 7) = 56
Therefore, the GCF (greatest common factor) = 56/56 = 1.

How to Find the LCM of 7 and 8 by Prime Factorization?

To find the LCM of 7 and 8 using prime factorization, we will find the prime factors, (7 = 7) and (8 = 2 × 2 × 2). LCM of 7 and 8 is the product of prime factors raised to their respective highest exponent among the numbers 7 and 8.
⇒ LCM of 7, 8 = 2³ × 7¹ = 56.