The 1963 March on Washington for Jobs and Freedom was a complex event with multiple themes and subthemes, including ending discrimination in hiring (331.133 Discrimination in employment); however, the overarching theme emphasized in most works is civil rights for African Americans. The number for that topic exists as a built number in WebDewey: 323.1196073 African Americans--civil rights, built with base number 323.11 Ethnic and national groups plus T5--96073 African Americans (United States Blacks), following the add note at 323.111-323.119 Specific ethnic and national groups. In the upward hierarchy is 323.1 Civil and political rights of nondominant groups. Both 323.1 and 323.11 have the standard-subdivisions-are-added note: "Standard subdivisions are added for either civil or political rights or both"; that signals that either topic alone is considered to approximate the whole, as well as both topics together.
For a work that focuses on the 1963 March, what can be added to 323.1196073African Americans--civil rights? The record for T5--96073 African Americans (United States Blacks) has this add note: "Unless it is redundant, add 0* to T5--96073 and to the result add notation T2--1-T2--9 from Table 2 for area, e.g., African Americans in England T5--96073042, African Americans in New York T5--960730747, but African Americans in United States T5--96073." The asterisk points to the footnote: "*Add 00 for standard subdivisions; see instructions at beginning of T5--0." The March was held in Washington, D.C., but the planners and participants came from all over the United States; hence adding 0 plus T2--753 District of Columbia (Washington) would not be appropriate. Adding 0 plus T2--73 United States would seem redundant after a number that already means "African Americans (United States Blacks)"; besides, the add note forbids it: "but African Americans in United States T5--96073." One can, however, express the time period by adding the standard subdivision T1--09046 1960-1969. To do that correctly, one must follow the instruction to "Add 00 for standard subdivisions." The final built number is 323.1196073009046 African Americans--civil rights--1960-1969.
In this case, the WebDewey number building tool does not automatically follow the instruction to "Add 00 for standard subdivisions"; one must click "Edit Local" to insert the extra zero. For instructions on use of the number building tool, including the "Edit Local" function, see the Dewey Training Courses site, especially the "Standard Subdivisions Number Building" unit. (It is not always necessary to use the "Edit Local" function to get an extra zero; see this previous post.) Here is the summary display of the built number 323.1196073009046 after the extra zero has been inserted:
Examples of works classed in 323.1196073009046 African Americans--civil rights--1960-1969 are Like a Mighty Stream: The March on Washington, August 28, 1963 and What Was the March on Washington? Both works have as first subject heading "March on Washington for Jobs and Freedom (1963 : Washington, D.C.)"; for the second work, the heading has the form subdivision "Juvenile literature."