If you're putting a whole sentence in parentheses, the custom follows logic -- put the period inside the parentheses, not outside it. Thus, for an example from a court case (in a state, California, ...

If you want to add parentheses in Excel, here is how you can do that. Although the manual method works pretty well when you want to add round brackets around one or two cells, you can use this guide ...

Formulas in Microsoft Excel can contain a wide range of symbols, such as the asterisk (*), the question mark (?), and the "at" (@) sign. Among the most important are parentheses, square brackets, and ...

Mary Norris, the Comma Queen, explains the order of operations for punctuation marks in asides and afterthoughts.