182 LearnersLast updated on May 26th, 2025
LCM of 7 and 9
LCM is a common multiple, the smallest value between the numbers 7 and 9. 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 7 and 9?
The LCM of 7 and 9 is 63. 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 7 and 9 Using Listing the Multiples
Step 1: Write down the multiples of the numbers. Don’t stop too early.
Multiples of 7 = 7, 14,21,28,35,42,49,56,63,70,…
Multiples of 9 = 9,18,27,36,45,54,63,…
Step 2:Find the smallest number common between the written multiples of 3 and 8
The smallest common multiple is 63
Thus, LCM(7,9) = 63
LCM of 7 and 9 Using Prime Factorization
Step 1: factorize the numbers into its prime factors
7 = 7×1
9 = 3×3
Step 2: find the highest powers of the factors of 7 and 9
Step 3: Multiply the highest powers
LCM(7,9) = 63
LCM of 7 and 9 Using Division Method
- Write the numbers 7,9 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(7,9) = 63
Common Mistakes and how to avoid them while finding the LCM of 7 and 9
Listed here are a few mistakes that one can commit when trying to find the LCM of the numbers 7 and 9. Try to avoid them.
Mistake 1
Listing incorrect multiples
If the LCM of given numbers is 63, double-check that the number appears on the list of both 7 and 9.
LCM of 7 and 9, examples
Problem 1
The LCM of 7 and 9 is 63. If the LCM increases by 20%, what is the new value?
Increase = 20%×63=0.2×63=12.6
New LCM = 63+12.6=75.6
Explanation
A 20% increase in the LCM of 63 results in 75.6.
Problem 2
Simplify the fraction LCM(7,9)/GCF(7,9).
LCM(7,9)=63, GCF(7,9)=1
Simplified fraction: 63/1=63
Explanation
The LCM divided by the GCF gives the value of the LCM in this case.
Problem 3
A car mechanic services a red car every 7 days and a blue car every 9 days. If the cars are serviced today, when will they be serviced next together?
The LCM of 7 and 9 is 63.
Explanation
Both cars will be serviced again in 63 days. The LCM of 7 and 9 is 63, which is the smallest common time interval for the given digits.
FAQs on LCM of 7 and 9
1.What is the HCF of 7 and 9?
2.What are the multiples of 7 and 9?
3.What is the LCM of 7,9,21 and 1?
4.What is divisible by 7 and 9?
5.What is the LCM of 6,7,9 and 12?
6.How can children in Indonesia use numbers in everyday life to understand LCM of 7 and 9?
7.What are some fun ways kids in Indonesia can practice LCM of 7 and 9 with numbers?
8.What role do numbers and LCM of 7 and 9 play in helping children in Indonesia develop problem-solving skills?
9.How can families in Indonesia create number-rich environments to improve LCM of 7 and 9 skills?
Important glossaries for the LCM of 7 and 9
- 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.
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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
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