Last updated on May 26th, 2025
LCM provides a tool to work the arithmetic operations of fractions, and it also assists when one needs to make a schedule or align a cycle of events which occur frequently.
Step 1: Record the multiples of each number;
4 = 4,8,12,16,20,24,28,…
7 = 7,14,21,28…
Step 2: Pick among the smallest multiple of 4 and 7 LCM
LCM(4,7) = 28
The Division Method involves simultaneously dividing the numbers by their prime factors and multiplying the divisors to get the LCM.
Step 1: Write down the numbers in a row;
Step 2: Divide the row of numbers by a prime number that is evenly divisible into at least one of the given numbers. Continue dividing the numbers until the last row of the results is ‘1’ and bring down the numbers that have not been divisible previously.
Step 3: The LCM of the numbers is the product of the prime numbers in the first column, i.e,
2×2×7= 28
LCM (4,7) = 28
Listed below are a few commonly made mistakes while finding the LCM of 4 and 7.
a=4,b=7, verify the relationship between the HCF and LCM of the numbers.
We can verify the relationship using LCM (a,b)×HCF(a,b) = a×b
LCM (4,7) = 28
HCF (4,7) = 1
28×1 = 4×7
28=28
Both sides are equal, the formula holds good. The above is how we verify the validity of the LCM and HCF obtained.
Use LCM(a,b) = aĂ—b/HCF(a,b) to find the LCM of 3 and 7.
The HCF of 4 and 7 is 1, they share no common factors.
Applying the formula;
LCM(a,b) = a×b/HCF(a,b)
LCM(4,7) = 4×7/1
LCM = 28
Using the above formula and the method we find the LCM of any two numbers
Is 28 a common multiple of 4 and 7. Verify.
To check if 28 is a common multiple of 4 and 7, we check the divisibility of the numbers;
28/4 = 7
28/7 = 4
28 is a common multiple of both 7 and 4 as there are no remainders left behind on division.
Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.
: She loves to read number jokes and games.