How to insert & edit Excel formulas
To enter a formula you can either select a cell and type '=' followed by the formula, as shown here:

Or...
Select the desired cell, then click the 'formula bar' and type in the formula (starting with the obligatory '=' sign), as shown here:

Once you've entered a formula, it will not show in the cell. The cell will show the result of the formula (there's a way around this that we'll discuss later).
To edit a formula once you've created it, do one of the following:
- Select the cell containing the formula and then edit the formula in the 'formula bar'
- Select the cell and press 'F2'. This will show the formula within the cell and allow you to edit it

