LCM for 9 and 21
What's the Least Common Multiple (LCM) of 9 and 21?
(Sixty-three)
Finding LCM for 9 and 21 using GCF's of these numbers
The first method to find LCM for numbers 9 and 21 is to find Greatest Common Factor (GCF) of these numbers. Here's the formula:
LCM = (Number1 × Number2) ÷ GCF
GCF of numbers 9 and 21 is 3, so
LCM = (9 × 21) ÷ 3
LCM = 189 ÷ 3
LCM = 63
Finding LCM for 9 and 21 by Listing Multiples
The second method to find LCM for numbers 9 and 21 is to list out the common multiples for both nubmers and pick the first which matching:
Multiples of 9: 9, 18, 27, 36, 45, 54, 63, 72, 81
Multiples of 21: 21, 42, 63, 84, 105
So the LCM for 9 and 21 is 63
Finding LCM for 9 and 21 by Prime Factorization
Another method to find LCM for numbers 9 and 21 is to list all Prime Factors for both numbers and multiply the highest exponent prime factors:
All Prime Factors of 9: 3, 3 (exponent form: 32)
All Prime Factors of 21: 3, 7 (exponent form: 31, 71)
32 × 71 = 63
Related Calculations
See Also
- Greatest Common Factor - Find the Greatest Common Factor (GCF) of two numbers
<a href="https://calculat.io/en/number/least-common-multiple-lcm-of/9--21">What is the LCM of 9 and 21? - Calculatio</a>
LCM Table
About "Least Common Multiple" Calculator
Least Common Multiple (LCM) also known as the Lowest Common Multiple or Smallest Common Multiple of 2 numbers - it is the smallest positive integer that is divisible by both numbers