The spreadsheet Apple Numbers identifies its spreadsheet with the extension numbers.
The data in a NUMBERS file is arranged in rows and columns and can be linked together using formulas and relationships. In addition to table cell values, formatting instructions, formulas, graphics, and images may also be included.
The format is based on XML. Numbers is also available as part of the Apple iWork Office suite.
Most often resolving problems with opening NUMBERS files is very simple. Just install an appropriate program that supports such files. All of the listed programs support NUMBERS files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of NUMBERS files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate NUMBERS files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the Apple Numbers applications is not on the list, select "Browse" option in order to manually locate the directory where Apple Numbers has been installed.
Sometimes problems with opening NUMBERS files may not lie with the application itself, but can arise due to other causes, such as: