You need at least two numbers to compare multiples.
The common multiples of 9 and 16 are 144, 288, 432 and so on.
lcm(4, 9) = 36 → the two least common multiples (ie the first two common multiples) of 4 and 9 are 36 and 72.
Those are known as "common multiples". The smallest POSITIVE of these common multiples is called the "least common multiple".
The two smallest multiples of 10 are 10 and 20. For them to be common, they would need to be compared to another set of multiples.
You need at least two numbers to find something in common.
The least common multiple of 30 , 32 = 480
The least common multiple, or LCM
Use some method which you probably already learned, to find the least common multiple. All the other common multiples are multiples of this least common multiple, so you can multiply the least common multiple by 2, by 3, by 4, etc., to get additional common multiples.
Short answer: There is none. There is not a least common multiple of a single number, such as 54, because there cannot be any form of common multiple without two or more numbers to compare. Common multiples are multiples that the numbers being compared have in common. The least common multiple is the smallest multiple that all the numbers being compared have in common. Thus, since there are not two or more numbers to compare, there is not a least common multiple. The lowest common multiple of 54 depends upon the other number(s) with which it has COMMON multiples and is one of the multiples of 54. The common multiples of 54 depends upon the other numbers with which 54 has COMMON multiples and are the multiples of the least common multiples between 54 and the other number(s).
You need at least two numbers to find an LCM.
You need at least two numbers to find an LCM.