Number Building
Only a fraction of potential DDC numbers are included in the schedules. It is often necessary to build or synthesize a number that is not specifically listed in the schedules. Such built numbers allow for greater depth of content analysis. There are four sources of notation for building numbers: (A) Table 1 Standard Subdivisions, (B) Tables 2–6, (C) other parts of the schedules and (D) add tables in the schedules.
Number building is initiated only upon instructions in the schedules (except for the addition of standard subdivisions, which may take place anywhere unless there is an instruction to the contrary). Number building begins with a base number (always stated in the instruction note) to which another number is added.