Download our free Excel workbook containing 60 tips, tricks and techniques 

Download this handy one-page guide to Excel's If function and related functions:

Download this guide to Excel's vlookup function:

This guide covers the more basic functions: sum, average, max, min, upper, lower, proper, trim, concatenate, left, right and find:

Five of the most common spreadsheet mistakes:

1.  Omitting $ signs from formulas when they need to be included - or putting them in the wrong place. A $ in a formula fixes what comes immediately after it, either the row or the column or both, when the formula is copied.

2. Accidentally putting a space after text. Excel will treat a word followed by a space as different from the word on its own - even though they look the same to the user. Use the Trim function to remove unwanted spaces.

3. Getting a "division by zero" error. You can't divide a value by zero or a blank cell. Use the Iferror function to avoid this.

4. Having numbers stored as text. They might look like numbers but Excel won't treat them as such. For a single value you can click on the warning and choose "Convert to Number". For a range of values you can multiply them all by one (use Paste Special, Multiply).

5. Not putting quotation marks round text when used in formulas (but you don't do this when using range names).