Last updated: before December, 1998
First check that you have that the field definition is numeric with the right number of decimal places.
While in design mode, select the field and then enter the Style/Field Format menu (v2.1, other versons may be different) and either select one of the custom numeric field formats provided, or enter your own. For exporting data, create and export a calculated field containing the formula:
NumToText(DB.NUMBER,'####.00')
where ####.00 is the output forumla you require.