Text can be entered by selecting a cell, typing the text and then typing the Enter key. Anything that is not interpreted to be a number, boolean, formula or error will be treated as a text field. To prevent Gnumeric from interpreting an entry as one of these other elements, a leading apostrophe can be added to force the entry to be text. Any entry, no matter what the contents, which starts with a leading apostrophe (') will be considered to be text.
Postal codes in the United States are series of five integers. By default, Gnumeric interprets these to be numbers. This interpretation means that the leading zeros used in the postal codes of the northeastern region will be lost by default. To retain these leading zeros, either the code should be entered with a leading apostrophe (e.g. '02917) or the cells should be formatted as text before data entry (see Section 5.10 ― Formatting Cells for an explanation of formatting).