Ranges - one of the most powerful features in Excel
The following sheet contains the monthly sales figures for ACME Gadget Company (on a per-salesperson basis).

To calculate the sales for Sam (the first sales man) we could use the following formula:
=B2+B3+B4+B5+B6+B7+B8+B9+B10+B11+B12+B13
Which adds the monthly sales figures for Sam from January to December. But entering this formula is very tedious.
Fortunately for us, there is a much simpler way.
We can use the SUM function, which receives a range of cells and sums them up. So an alternative to the previous formula will be
=SUM(B2:B13)
Which is much easier to enter and will return the same result.
As you can see, a range is a group of cells defined by the first and last cell in the group and separated by a colon.
In the previous example we defined a range that was part of a column. But ranges aren't limited to be just column shaped.
As you can see below, we can use a range to sum up the total sales for the month of April.
The formula for that range would be:
=SUM(B5:F5)

We can also use ranges to SUM up the entire yearly sales, by using the following formula:
=SUM(B2:F13)
As shown here:

In this case the range we used includes all the data within the rectangle which begins on cell B2 and ends on cell F15.
* The blue rectangle is shown for illustration purposes -it doesn't appear in a normal Excel sheet.

