Microsoft word 2010 compatibility

I sent out a few documents to some people in 2010 word and they can’t seem to open them up. They say they have earlier versions.
Will the older versions not open the 2010 documents?
If not can somebody tell me how to put them in pdf format such as adobe?
Thanks in advance and apologize for posting such a noob question here lol
Answer #1
File -> Save as –> just below the file name you have a option save as type and a dropdown box, open it and select word 97-2003 document . Now they can be accessed by older versions too
Answer #2
Or you can tell them to download the Microsoft Office Compatibility Pack. After they install it, they can open up Word 2010 documents.
http://www.microsoft.com/download/en/details.aspx?id=3
Answer #3
vigk replied: File -> Save as --> just below the file name you have a option save as type and a dropdown box, open it and select word 97-2003 document . Now they can be accessed by older versions too
This.
I have to use this option in work, as most companies cannot open .Docx.
They usually cannot install anything like Microsoft Office Compatibility Pack as they don’t have the permissions to be able to on corporate pc’s.