# Excel Sum

## Excel Sum, Average And Count

A function is a special key word which can be entered into a cell in order to perform a process on some data in your spreadsheet. When you type in a function into a cell, it will take the form

```
=Function(data)
```

The data referred to in the function can be the contents of an individual cell or a range of cells, and is called the *argument*
of the function. Excel comes with a whole range of useful functions, and you'll probably find it impossible to remember the names of them all.
This is where the *Insert Function* button comes in. This button is found to the left of the Formula Bar, immediately above the spreadsheet cells.

In this tutorials, we're looking at the sum, average and count functions, and the chances are that you'll be able to remember their names. You can probably guess that they apply to a range of cells containing numbersand calculate the total sum, aritmetic mean and the number of values in the range.

For example, consider the following values in a spreadsheet:

We have a list of monthly figures for sales and we need to find the yearly total. To do this, type the following into cell B14:

```
=SUM(B2:B13)
```

As soon as you press enter, Excel calculates the sum. The same principle applies to the average and count functions:

- =AVERAGE(B2:B13)
- =COUNT(B2:B13)