The area code plus local number can have varying total and composite digit lengths,for historical and operational reasons,but as a rule they do not exceed 11 digits in combined length. For readability,and to distinguish geographic location,telephone numbers are oftenspoken,displayed andpublished with a gap between the area code and local number,and/or with the area code in brackets. Problems occur for the reader when this spacing or formatting is incorrectly applied by the publisher.