Convert gnumeric to csv

What is the difference between .gnumeric and .csv?

Description: Gnumeric Spreadsheet is a free and open-source spreadsheet program developed for the GNOME desktop. It is designed to read and write both Microsoft Excel and OpenDocument Formats, and can export to a variety of other formats. It is well-suited for tasks such as data analysis and manipulation, as well as basic calculations.; A CSV file is a comma separated values file commonly used by spreadsheet programs such as Microsoft Excel or OpenOffice Calc. It contains plain text data sets separated by commas with each new line in the CSV file representing a new database row and each database row consisting of one or more fields separated by a comma. CSV files are often opened by spreadsheet programs to be organized into cells or used for transferring data between databases.