Numbers is a spreadsheet application developed by Apple as part of the iWork suite. Files using the .numbers extension are spreadsheets created with this application. Numbers differentiates itself from Excel by allowing multiple independent tables on a single canvas, rather than a single infinite grid. It is optimized for visual data presentation on Mac and iOS devices. Sample Numbers files are used to test Apple's spreadsheet capabilities and iCloud sync features. Developers use them to check how complex sheets with multiple tables and charts look on different devices. They are also used to test export functionality to ensuring that data structure is preserved when converting to CSV or Excel formats.