Answer

I have no idea in how many days the world was created. That depends on what exactly is meant by creation and what each stage was. But indeed I do not see any necessity to assume that it was, meaning to take the biblical description literally. There are two differences between the creation of the world and the miracles described in the Hebrew Bible (Tanakh):
1. The description of creation looks and reads like a myth, not like a historical account, even without all the scientific knowledge we have today. It is entirely wrapped in supernatural mystery. From Abraham onward, however, the Torah seems to move into historical narration. Nachmanides already wrote that the Account of Creation is entirely a secret. When you have a historical description within which miracles appear, it is reasonable to think the intention is to describe a miracle, not a parable. But when you have a description whose entire character is mythic, it is reasonable to assume that it is a parable.
2. Creation in seven days contradicts the facts, not the laws of nature. Science today knows how to give a fairly good account of creation, and it is not similar to what is described in the Torah. Miracles, by contrast, contradict the laws of nature, not facts. Think, for example, about someone who comes and tells you that a miracle happened to you this morning and you were saved from death. You do not reject his claim because you know miracles do not happen, but because you know it did not happen. So too, when the Torah tells of the creation of the world, I reject it not because it is a miracle or deviates from the laws of nature—on the contrary, in my view creation is required by reason—but because the facts show that it is not correct.