Although in the past, AppleWorks 6 was able to open almost all Word & Excel documents, it is not able to open those saved with newer versions of either Mac or PC application. The Office translators in AppleWorks were introduced in late 2000 or early 2001 & have not been updated. In the meantime, Microsoft has made significant changes in the file formats & AppleWorks can't open them any more. AppleWorks 6 was released in March, 2000, & hasn't even had any kind of update since January, 2004.
Your best option would be to use a free Office clone such as LibreOffice or Numbers, part of iWork.