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346 LearnersLast updated on August 5, 2025
LCM of 5 and 8
LCM is a common multiple, the smallest value between the numbers 5 and 8. Did you know? We apply LCM unknowingly in everyday situations like setting alarms and to synchronize traffic lights and when making music.
What is the LCM of 5 and 8?
The LCM of 5 and 8 is 40. We can find the LCM using the Listing multiples method, the prime factorization method and the long division method. These are explained below.
LCM of 5 and 8 Using Listing the Multiples
Step 1: Write down the multiples of the numbers. Don’t stop too early.
Multiples of 5 = 5,10,15,20,25,30,35,40,…
Multiples of 8 = 8, 16,24,32,40,…
Step 2: Find the smallest number common between the written multiples of 5 and 8
The smallest common multiple is 40
Thus, LCM(5,8) = 40
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LCM of 5 and 8 Using Division Method
- Write the numbers 5,8 in a row
- Divide them by their common prime factors, if there is one
- Carry forward the numbers that are left undivided by the previously chosen factor
- Continue dividing until the remainder is ‘1’
- Multiply the divisors to find the LCM
- LCM(5,8) = 40
Common Mistakes and how to avoid them while finding the LCM of 5 and 8
Listed here are a few mistakes that one can commit when trying to find the LCM of the numbers 5 and 8. Try to avoid them.
Mistake 1
Listing incorrect multiples
If the LCM of given numbers is 40, double-check that the number appears on the list of both 5 and 8.
Mistake 2
Prime factorization errors
Check if the numbers are prime factored correctly. For example, we may accidentally write 8 = 2×2×3 instead of 8= 2×2×2
Mistake 3
Thinking product is the LCM
One may think the product of the numbers is the LCM of the numbers. This is only true in case of co-prime numbers.
LCM of 5 and 8, Examples
Problem 1
One cookie jar is filled every 5 hours, and the candy jar is filled every 8 hours. If the jars started filling at the same time, how long will it take for the both of them to be filled?
The LCM of 5 and 8 is 40.
Explanation
Both jars will be filled at the same time again in 40 hours, which is the LCM of the given numbers, expressing the smallest time interval.
Problem 2
Find the LCM of 5ยฒ and 8ยฒ.
52=25
82=64
Now find the LCM of 25 and 64. The prime factorizations are:
25=52
64=22
The LCM is found by taking the highest powers of all prime factors:
LCM(25,64)=52×26=25×64=1600
Explanation
So, the LCM is 1600.
Problem 3
By what percentage must 5 be increased to reach the LCM of 5 and 8?
The LCM of 5 and 8 is 40. Now, calculate the percentage increase from 5 to 40:
Percentage Increase=(540−5โ)/5×100=35/5โ×100=700%
Explanation
So, 5 must be increased by 700% to reach 40.
FAQโs on LCM of 5 and 8
1.What is the LCM of 4,5 and 8?
2.What is the HCF of 5 and 8?
3.What are the factors of 8 and 5?
4.What is the LCM of 12 and 15?
5.What is the LCM of 16 and 20?
Important glossaries for LCM of 5 and 8
- Multiple — product of a number and a natural integer
- Prime factor — number one gets after prime factorization any given number
- Prime factorization — the process of breaking the number into its prime factors.
Hiralee Lalitkumar Makwana
About the Author
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.
Fun Fact
: She loves to read number jokes and games.
