What do the little numbers at end of paragraphs mean in book

The little numbers at the end of paragraphs in a book are called reference numbers. They refer to notes found at the bottom of the page, or sometimes at the end of the chapter or book. Notes provide additional information related to the paragraph to provide a deeper context without interrupting the reader’s main focus. These additional pieces of information include clarifications, historical notes, citations, sources used, bibliography, etc. References provide valuable insights to better understand a specific content of the book.