Structured document created by Mathematica, an application used for mathematical and scientific computation; may store text, images, audio, functions, and interactive user interface elements; allows mathematical results to be viewed in an interactive document. Notebook files are saved in a plain text format. Their data is arranged in cells, similar to a standard spreadsheet. Notebooks can be exported to many different file formats, including raster graphic, GIS, compressed, and spreadsheet formats. NOTE: The "DefaultStyles.nb" file is used as the default style sheet for new notebooks. Notebooks can be opened using the NotebookOpen command within a Mathematica function.