Classification is the act of organizing things into groups based on what they have in common. When a librarian uses classification to arrange books, she might put all the mysteries together, all the science books together, and all the biographies together. Scientists use classification to organize living things: mammals in one group, reptiles in another, insects in a third.

The system you use for classification depends on what matters most for your purpose. You might classify your clothes by type (shirts, pants, socks) or by season (winter clothes, summer clothes). A teacher might classify math problems by difficulty level or by the skill they practice.

Good classification makes things easier to find and understand. Imagine trying to locate a book in a library where everything was just piled randomly! The Dewey Decimal System is a famous classification system that gives every book a number based on its subject, so libraries everywhere can organize books in the same way.

When scientists discover a new species, they work hard to determine its proper classification among all living things. Where does it fit? What other creatures is it related to? Classification helps us see patterns and relationships we might otherwise miss.