LCM of 7 and 56
LCM of 7 and 56 is the smallest number among all common multiples of 7 and 56. The first few multiples of 7 and 56 are (7, 14, 21, 28, 35, 42, 49, . . . ) and (56, 112, 168, 224, . . . ) respectively. There are 3 commonly used methods to find LCM of 7 and 56 - by listing multiples, by prime factorization, and by division method.
1. | LCM of 7 and 56 |
2. | List of Methods |
3. | Solved Examples |
4. | FAQs |
What is the LCM of 7 and 56?
Answer: LCM of 7 and 56 is 56.
Explanation:
The LCM of two non-zero integers, x(7) and y(56), is the smallest positive integer m(56) that is divisible by both x(7) and y(56) without any remainder.
Methods to Find LCM of 7 and 56
The methods to find the LCM of 7 and 56 are explained below.
- By Division Method
- By Listing Multiples
- By Prime Factorization Method
LCM of 7 and 56 by Division Method
To calculate the LCM of 7 and 56 by the division method, we will divide the numbers(7, 56) by their prime factors (preferably common). The product of these divisors gives the LCM of 7 and 56.
- Step 1: Find the smallest prime number that is a factor of at least one of the numbers, 7 and 56. Write this prime number(2) on the left of the given numbers(7 and 56), separated as per the ladder arrangement.
- Step 2: If any of the given numbers (7, 56) 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 56 is the product of all prime numbers on the left, i.e. LCM(7, 56) by division method = 2 × 2 × 2 × 7 = 56.
LCM of 7 and 56 by Listing Multiples
To calculate the LCM of 7 and 56 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, 35, 42, 49, . . . ) and 56 (56, 112, 168, 224, . . . . )
- Step 2: The common multiples from the multiples of 7 and 56 are 56, 112, . . .
- Step 3: The smallest common multiple of 7 and 56 is 56.
∴ The least common multiple of 7 and 56 = 56.
LCM of 7 and 56 by Prime Factorization
Prime factorization of 7 and 56 is (7) = 71 and (2 × 2 × 2 × 7) = 23 × 71 respectively. LCM of 7 and 56 can be obtained by multiplying prime factors raised to their respective highest power, i.e. 23 × 71 = 56.
Hence, the LCM of 7 and 56 by prime factorization is 56.
☛ Also Check:
- LCM of 3, 5 and 7 - 105
- LCM of 30, 72 and 432 - 2160
- LCM of 8 and 11 - 88
- LCM of 7, 8, 11 and 12 - 1848
- LCM of 36 and 42 - 252
- LCM of 5, 10, 15 and 30 - 30
- LCM of 9 and 13 - 117
LCM of 7 and 56 Examples
-
Example 1: The GCD and LCM of two numbers are 7 and 56 respectively. If one number is 7, find the other number.
Solution:
Let the other number be p.
∵ GCD × LCM = 7 × p
⇒ p = (GCD × LCM)/7
⇒ p = (7 × 56)/7
⇒ p = 56
Therefore, the other number is 56. -
Example 2: Verify the relationship between GCF and LCM of 7 and 56.
Solution:
The relation between GCF and LCM of 7 and 56 is given as,
LCM(7, 56) × GCF(7, 56) = Product of 7, 56
Prime factorization of 7 and 56 is given as, 7 = (7) = 71 and 56 = (2 × 2 × 2 × 7) = 23 × 71
LCM(7, 56) = 56
GCF(7, 56) = 7
LHS = LCM(7, 56) × GCF(7, 56) = 56 × 7 = 392
RHS = Product of 7, 56 = 7 × 56 = 392
⇒ LHS = RHS = 392
Hence, verified. -
Example 3: Find the smallest number that is divisible by 7 and 56 exactly.
Solution:
The smallest number that is divisible by 7 and 56 exactly is their LCM.
⇒ Multiples of 7 and 56:- Multiples of 7 = 7, 14, 21, 28, 35, 42, 49, 56, . . . .
- Multiples of 56 = 56, 112, 168, 224, 280, 336, 392, . . . .
Therefore, the LCM of 7 and 56 is 56.
FAQs on LCM of 7 and 56
What is the LCM of 7 and 56?
The LCM of 7 and 56 is 56. To find the LCM (least common multiple) of 7 and 56, we need to find the multiples of 7 and 56 (multiples of 7 = 7, 14, 21, 28 . . . . 56; multiples of 56 = 56, 112, 168, 224) and choose the smallest multiple that is exactly divisible by 7 and 56, i.e., 56.
If the LCM of 56 and 7 is 56, Find its GCF.
LCM(56, 7) × GCF(56, 7) = 56 × 7
Since the LCM of 56 and 7 = 56
⇒ 56 × GCF(56, 7) = 392
Therefore, the GCF = 392/56 = 7.
What are the Methods to Find LCM of 7 and 56?
The commonly used methods to find the LCM of 7 and 56 are:
- Listing Multiples
- Division Method
- Prime Factorization Method
What is the Relation Between GCF and LCM of 7, 56?
The following equation can be used to express the relation between GCF and LCM of 7 and 56, i.e. GCF × LCM = 7 × 56.
What is the Least Perfect Square Divisible by 7 and 56?
The least number divisible by 7 and 56 = LCM(7, 56)
LCM of 7 and 56 = 2 × 2 × 2 × 7 [Incomplete pair(s): 2, 7]
⇒ Least perfect square divisible by each 7 and 56 = LCM(7, 56) × 2 × 7 = 784 [Square root of 784 = √784 = ±28]
Therefore, 784 is the required number.
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