Abstract: Method and apparatus for use in numbering a series of successively fed documents with consecutive serial numbers and corresponding check digits, including weighted, non-sequential check digits. The check digits are independently applied by a single, engraved wheel mounted on the periphery of a rotating sleeve and positioned by an eccentrically-mounted electronically-controlled stepping motor, with the consecutive serial numbers being applied by a conventional consecutive decimal numbering head mounted to a separate, rotating shaft. Multiple check digit wheels and/or multiple consecutive decimal numbering heads may be employed.