Since 63 is a multiple of 9, it is automatically the LCM.
The LCM of 9 and 21 is 63, which is the multiple of the highest power of prime factors from both numbers, is 63. (3² x 7 = 3 x 3 x 7 = 63).
There cannot be a least common multiple if there are not at least two numbers. The least common multiple is the smallest number that is a multiple of the two (or more) numbers. For example, the least common multiple of 4 and 6 is 12. The multiples of 63 are 63, 126, 189, 252, 315, 378, 441, ...
3, 7, 9
It is not possible to give a sensible answer to this question. The least common multiple (LCM) refers to a multiple that is COMMON to two or more numbers. You have only one number in the question!
The LCM of 7 and 9 is 63.
10 and 63
The LCM of 7 and 9 is 63.
The LCM of 7 and 9 is 63.
9 and 21
You don't. You need at least two numbers to find an LCM.
63 = 3 x 3 x 7, so there are more than one combination: 7 & 9 and 21 & 9. That should be it, unless you want to consider the somewhat trivial combinations : 63 & 21, 63 & 9, 63 & 3, 63 & 7.
7 and 9
The least common multiple is the smallest number that is multiple of two or more numbers. 21: 21, 42, 63 63: 63 The LCM of 21 and 63 is 63.
Since 63 is a multiple of 9, it is automatically the LCM.
The LCM is: 63
The LCM of 9 and 21 is 63, which is the multiple of the highest power of prime factors from both numbers, is 63. (3² x 7 = 3 x 3 x 7 = 63).