Working with Numbers files on Windows machines
For someone who has never touched Mac computer his of hers whole life it can be sometimes very challenging to deal with files and formats from OS X platforms on standard Windows machines. Like when your apple-enthusiastic friend sends you a document or presentation in one of the former iWorks formats and you are like WTF, how am I supposed to open these damned files?
For someone familiar with Excel, getting document in a .numbers file can be nightmare, because almost no Windows program uses or supports it and thus it is largely unknown for most casual Office users. So what is .numbers file?
Well, it's just a a spreadsheet document created in Apple's spreadsheet program called Numbers. Now most users will probably wonder how to open these NUMBERS spreadsheets and thus it is not really surprising that this question is somewhat common on internet.
UPDATE: A new article called Open and convert Numbers spreadsheets online was published and may contain new and useful information about this subject.
How to open or work with Numbers spreadsheets without the program
Ask your friend
The easiest solution how to open .numbers spreadsheet on Windows PC would be to ask your friend (or the person that did send you the file), to send the spreadsheet in different format.
Numbers offers export of .numbers spreadsheets to other formats, including XLS (used by Microsoft Excel), CSV (Comma Separated Value), or even common PDF (opened with Adobe Reader), all of which should be accepted in other programs.
If you want to further work with your spreadsheet, it would be best to ask for .xls file. CSV format is good if you are only interested in the data and not much in formatting, whilst PDF is good enough if you just want to view or print the document.
Opening numbers without Mac
If you do not have access to Numbers, you may have success with LibreOffice Calc spreadsheet editor that should support .numbers files. This function was added in 2015 for users that need to work with both OS X and Windows spreadsheet formats.
Your last option would be a document conversion. You can find document conversion utilities that should allow you to convert numbers to xls or similar formats. There are also online conversion services like ZAMZAR, that offer plenty of various conversions and support huge number of formats.
Once you have .xls file, you can open it in almost any spreadsheet editor and work with your document.
Share it with others
Do you know more about this topic? Have you found some handy convertor that is able to directly convert .numbers spreadsheets to .xls or some other spreadsheet format ? Don't be shy and share your experience with others.