classification numbers

The Dewey Decimal Classification (DDC) system is a system of library classification used to organize and arrange books and other materials in a library. It was developed by Melvil Dewey in the 1870s and is still in widespread use today.

The DDC is based on a system of ten main classes, each representing a broad subject area. These main classes are further divided into smaller divisions, and then into even smaller sections until each book or material is assigned a unique classification number. The classification numbers are arranged in a decimal format, with the first digit representing the main class, the second and third digits representing the division, and so on.

For example, the number “500” represents the natural sciences and mathematics, while the number “540” represents chemistry and “550” represents earth sciences. Within the earth sciences section, the number “550.1” represents geology, and “550.2” represents meteorology.

The DDC is used to organize and arrange books and materials in a library, and to help library patrons find the materials they are looking for. It is also used to create library catalogs and bibliographies.