Last updated on May 26th, 2025
The smallest integer that divides the numbers with no numbers left behind is the LCM of 20 and 28. Did you know? We apply LCM unknowingly in everyday situations like setting alarms and to synchronize traffic lights and when making music. In this article, let’s now learn to find LCMs of 20 and 28.
We can find the LCM using the listing multiples method, prime factorization method and the long division method. These methods are explained here, apply a method that fits your understanding well.
List the multiples of each of the numbers;
20 = 20,40,60,80,100,120,140,…
28 =28,56,84,112,140,…
Find the smallest number in both the lists
LCM (20,28) = 140
Prime factorize the numbers
20 = 2×2×5
28= 2×2×7
find the highest powers
2,2,5,7
Multiply the highest powers of the numbers
LCM(20,28) = 140
Listed here are a few mistakes children may make when trying to find the LCM due to confusion or due to unclear understanding. Be mindful, understand, learn and avoid!
The LCM of 20 and 28 is what percentage of their product?
LCM(20,28)=140
Product of 20 and 28: 20×28=560
Percentage = LCM/Product×100
140/560×100 =25%
The LCM is 25% of the product of the numbers.
The LCM of two numbers is 140, and one of the numbers is 28. If the LCM is 70% of the product of the two numbers, find the other number.
Let the other number be x
Given: LCM/28×x=0.7
140=0.7×28×x140 = 0.7×28×x
x=140/0.7×28 =7
7 is the other number.
Verify the relationship LCM (20,28)×GCF(20,28)=20×28.
LCM(20,28)=140
GCF(20,28)=4 (Common prime factorization: 22)
Left-hand side: 140×4=560
Right-hand side: 20×28=560
Since both sides are equal, the relationship holds true.
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.