You are an inexperienced Excel user and don’t know how to create your own formulas. You want to use one of the preconfigured formulas but it doesn’t appear in the Formulas tab ribbon. What can you do?

If you are unable to find a preconfigured formula in the Formulas tab ribbon in Excel, there are a few things you can try:

1. Check the Formula Library: Sometimes, certain formulas are categorized under specific groups within the Formula Library. Click on the "Formulas" tab in the ribbon, and then navigate to the relevant category such as "Math & Trig", "Logical", or "Text". Look for the formula within the appropriate category.

2. Use the Insert Function Dialog Box: Excel provides an Insert Function dialog box that allows you to search for specific formulas. Click on the "Formulas" tab in the ribbon and then click on the "Insert Function" button (fx) to open the dialog box. Here, you can search for the formula by its name or a keyword related to its functionality.

3. Explore Formula AutoComplete: When typing a formula directly into a cell, Excel provides Formula AutoComplete suggestions. Start typing the name of the formula you need, and Excel will suggest matching formulas to choose from. Press the Tab key to autofill the selected formula.

4. Use the Help Function: Excel has a built-in Help function that provides detailed information on various Excel features, including formulas. Press F1 on your keyboard or click on the "Help" button (?) in the ribbon to access the Help function. Search for the name of the formula you're looking for, and it will provide information on how to use it.

5. Confirm the Excel Version: If you have recently upgraded or installed a new version of Excel, it's possible that the formula you need might not be available in that specific version. Check the version of Excel you are using and cross-reference it with the available formula list for that version.

If you have exhausted these options and are still unable to find the formula you need, it's possible that you may need to install an add-in or consider writing a custom formula using Excel's built-in functions.

Why are you not trying to answer these yourself? You must have been given a text (book or online) to study from. If you haven't, you should invest in a copy of Excel for Dummies (and no, that's not meant to be insulting; it's an excellent book).