I'm unable to format a column of cells to all me to insert ZIP+4. The system reads the hyphen, e.g., 65721-0577, as a minus sign and executes the unintened function. This is intolerable.
This is all you need. Fix it or tell me how to create a cell that accepts ZIP+4.
That's the expected behaviour for a spreadsheet.
Format the cell as text or precede the value with an apostrophe, e. g.:
'65721-0577