Filing Classified Entries 

By classified entries, we mean entries which hear notation; that is, Class Number and Call Number entries. A Subject Catalogue and an Alphabetico-Classed Catalogue also are known as Classified Catalogues. Ranganathan considers a Classified Catalogue as a "Catalogue in which some entries are number entries and some are word entries". 

Filing of number entries will be easy when a simple scheme of Classification like Dewey Decimal Classification is used. The numerals and their sequential value is quite familiar to us. So the arrangement is simple. 

For example when numbers like 030; 360; 130; 505; 330; 720; etc., are to be arranged we an-arrange them in the sequence 

030 

130 

330 

360 

505 

720 

Similarly, when Class Numbers are based on pure notation using letter of alphabets like ABCD we can conveniently arrange them in a sequential order 

AAC 

AAH 

AAL 

ABC 

ABG   

ABK

ACD 

ACM and so on 

When both - alphabet letters and numerals are used in a mixed notation their arrangement needs some guidance as to whether letters should be taken first or numerals. If both capital letters and small letters are used and in addition both Arabic numerals and Roman numerals are also mixed up, then again some guiding principles of preference and sequence are needed. Filing becomes much more complicated when characters and symbols like - " " &; etc., appear as indication digits.