# Excel - How to Use Functions

This document explains how to use and edit functions in all versions of Microsoft Excel.

#### To perform a mathematical function on a group of cells, follow these steps:

- Select the cell that will contain the answer. All functions in Excel start with an equals sign,
**=**. - Type in the function that you would like to calculate. You can select a cell or group of cells as variables.
*For example, to add the value in cell A1 to the value in cell A2, you can type in the function***=A1 + A2**.*An alternative method:*- Type
**=** - Select cell A1 with the mouse
- Type
**+** - Select cell A2 with the mouse

- Type
- Press
**Enter**on the keyboard when you are done and wish Excel to calculate the answer.

#### To edit a function after it has been created:

- Select the cell that contains the function. The calculated answer will be displayed in the cell.
- Click on the
**Formula Bar**.After clicking in the Formula Bar, the function itself will now be displayed in the cell. You can edit the function from in the cell or in the formula bar. After the changes have been made, press

**Enter**to calculate and display the new answer in the cell.

#### Using pre-defined functions:

Excel also contains a number of pre-defined functions. To access these, click the**button on the Standard Toolbar, or select**

*Fx***Function**from the

**Insert**menu.

For example, the **Sum** function can be used to add up a range of cells.

- Select the cell that is to contain the answer.
- Type in
**=sum(**Two alternative methods:

- Click the
**Fx**button

or - Select
**Insert->Function**from the menu bar

- Click the
- Select the range of cells that the function is to be performed upon. You can also enter this directly by typing in the first cell in the range, a colon and then the last cell in the range - for example
**(A1:A2)**. - Type in a close parenthesis,
**)**. - Press
**Enter**on the keyboard to calculate and display the answer.