Which numerical classification system organizes library materials by subject into ten main classes?

• A. Dewey Decimal System
• B. ISBN (International Standard Book Number)
• C. Metadata
• D. Diversity (Collection Development)

Answer: (A)

Classifying library materials by subject using ten broad categories is the Dewey Decimal System. This system places items on shelves according to their subject, starting with a main class that represents a wide area of knowledge and then dividing that area into more specific topics. The ten main classes cover broad domains such as 000 for computer science and general works, 100 for philosophy and psychology, 200 for religion, 300 for social sciences, 400 for language, 500 for science, 600 for technology, 700 for arts and recreation, 800 for literature, and 900 for history and geography. Within each main class, items are given further numerical detail to reflect more precise topics, creating a hierarchical, subject-based organization that makes it easier to find related materials.

ISBN, on the other hand, is a unique identifier assigned to a specific edition of a book, not a system for organizing materials by subject. Metadata refers to information about data that describes a book (like author, title, and publication details), and Diversity (Collection Development) relates to goals for building a varied library collection rather than a cataloging method.