Last updated on May 26th, 2025
The meaning of least common factor (LCM) is to find the smallest number that divides any two integers evenly. LCM is used mainly in fractions to find a common number for both the integers. We use LCM for solving problems, lining up cycles or even synchronizing of events, also to schedule tasks in everyday life.
We use LCM of 40,36 and 126 to find the smallest number that divides both the numbers equally. The smallest positive number is the number that divides both numbers equally, is 1260 without leaving any remainder. LCM is used mainly in fractions to find a common number for both the integers.
The LCM of 40,36 and 126 can be found by the following methods like division method, listing multiples, prime factorization.
In division method, we divide both the numbers, we begin with dividing side by side the smallest number. We continue dividing until we get a common number that divides both the numbers equally. It makes it easier for the children to focus on prime factors and identify them.
Now multiply the divisors : 2×2×2×3×3×5×7=1260 which is the LCM.
Start by listing multiples of both the numbers separately:
Multiples of 40: 40, 80, 120, 160, 200, 240, 280, 320, 360, 400, 440, 480, 520, 560, 600...
Multiples of 36: 36, 72, 108, 144, 180, 216, 252, 288, 324, 360, 396, 432...
Multiples of 126: 126, 252, 378, 504, 630, 756, 882, 1,008, 1,134, 1,260...
The least common factor from the list is 1260. Therefore, the LCM of 40,36, and 126 is 210.
We part both the numbers unto factors:
Factor of 40: 23×5
Factors of 36: 22×32
Take the powers of both the numbers and multiply together:
LCM=23x32x5x7=1260.
While solving problems based on the LCM of 40,36 and 126 , children fail to understand few concepts, to give an idea of the mistakes, given below are a few mistakes and solutions of how to avoid them:
Find the product of two numbers if their LCM is 252 and their GCD is 18.
Formula: LCM(a, b) x GCD(a, b)= a × b
252 × 18 =4536
The product of the two numbers is 4536.
If a=40 and LCM(a, b)=360, find b.
Answer: b = 9.
LCM(a, b)= ab/GCD(a,b)
LCM(40,b)=360
GCD(40,b)=1
360= 40 × b/1
b=9.
If the LCM of 36, 40, and a number z is 5040, find the smallest value of z.
z=7.
LCM(36, 40) = 360
LCM(360, z) = 5040
z must contain the missing factor 7.
Thus, z=7.
What is the smallest 4-digit number divisible by the LCM of 40 and 126?
The smallest 4-digit number divisible by 2520 is 2520.
LCM(40, 126) = 2520
Smallest 4-digit number is 1000.
Divide: 1000÷2520≈0.3961000 ÷ 2520 ≈ 0.3961000÷2520≈0.396,
so the first multiple is 2520 itself.
The smallest 4-digit number divisible by 2520 is 2520.
Find the sum of the first three multiples of the LCM of 36 and 126.
The sum is 1512.
LCM(36, 126) = 252
First three multiples: 252, 504, 756
Sum = 252 + 504 + 756 = 1512
therefore, The sum is 1512.
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.