When and why are range cells selected in Excel?

Answer 1

Because it is a faster and simpler way or referencing a group of cells. You could use the individual cells like this to sum them:

=A2+A3+A4+A5+A6+A7+A8+A9+A10

Using a range reference you could do it like this:

=SUM(A2:A10)

Answer 2

There is no simple answer to that. There are many reasons to select ranges, such as doing calculations, formatting them, deleting them, copying them, cutting them etc. When is a matter for you, so you do it when you need to. So if you have a need to format a range of cells, then that is when you need to select them. If you need to copy a range of cells, then that is when you need to select them, and so on. So there are many reasons, and you do it when you need to do it.

Answer 3

It is a group of cells. A lot of actions are done on many cells, so referring to a range is very useful. You could be getting a total of a lot of cells for example.