Total price = unit price × quantity. The library originated from the habit of taking notes. The library is a special place for readers to use library documents. The reading room of a library is generally divided into general reading room, professional reading room and reference research room.

A library is an institution that collects, sorts out and collects books and materials for people to read and refer to. As early as 3000 BC, libraries appeared. Library has the functions of preserving human cultural heritage, developing information resources and participating in social education. Library is the external storage and selective transmission mechanism of social memory (usually expressed in written records). In other words, the library is the memory device and diffusion device of social knowledge, information and culture. Smoking is strictly prohibited in the library. Keep the room clean and tidy. It is forbidden to bring food and drinks into the library. Please don't drag the reading desk and chair at will. Keep the room quiet. Please turn off or mute the pager and mobile phone when you enter the library. Please speak softly in the library so as not to affect others' reading.