Standard Subdivisions, Page 3

Because the DDC is designed to allow the use of these subdivisions with most subjects in the schedules, the editors prefer to indicate the range of notations allowable within most of these subjects. To allow for further expansion of the sections of the DDC as new knowledge is discovered, many times the range of notation numbers set aside for the standard subdivisions includes one or more ‘0’ digits, as place holders to free shorter notations up for subject expansion of the schedules. These standard subdivisions with extra zeros will usually be found in subjects at the thousand sections level of the DDC breakdown. Look at the schedule for 641 "Food and drink."  It can be found on pages 479-480 of the 13th Abridged Edition. 

In this example, look at the section for Food (641.3). While no specific mention of Standard Subdivisions is given in the notes under ‘Food’, looking at the first notations listed under this heading shows that they are the same as the first two sections of the Standard Subdivisions Summary from Table 1. The actual heading of ‘Standard Subdivisions’ is listed finally with the number range ‘.300 3--.300 9’ Again, we are not given a base number, but are shown the number ranges to fit the subjects from the Standard Subdivisions table into. Using this example, a dictionary (--03) of Food would have the following notation:

641.3003