What do you mean?
What is the least common denominator (LCD) of 1/2468? It's only one number, so the LCD is just 2468.
What is the LCD of 2, 4, 6, and 8?
2 = 2
4 = 2 * 2
6 = 2 * 3
8 = 2 * 2 * 2
It's like we're making a parts list that can be used to make any of these numbers (2, 4, 6, 8). In this case our parts list is 2 * 2 * 2 * 3 because that list contains enough parts to make 2, 4, 6, or 8.
2 * 2 * 2 * 3 = 24
Answer: The LCD is 24.