Fortunately, Excel provides built-in features that allow you to hide and password-protect your worksheets without requiring any programming skills. Password Protecting Excel Spreadsheet Data ...

Here is a tutorial to lock or hide only the formula cells in an Excel workbook. You can also lock formulas in all worksheets in a workbook.

This is the demonstration file to accompany the article, Hide everything but the working area in an Excel worksheet by Susan Harkins.