If you've ever been an Appleworks user and you open a CWK - ClarisWorks Document and it will seem strangely familliar. In fact, if you found yourself thinking CWK-ClarisWorks Documents and Appleworks are exactly the same, you'd not be short of the mark. In 1998, Apple aquired Clarisworks and promptly renamed it Appleworks, though the latter was discontinued and hasn't been updated since 2004.
Anyhow, you can use a CWK - ClarisWorks Document for word processing, as a spreadsheet or for presentation. Iwork applications can still open it - (Numbers, Pages, Keynote) - though the file has to be in Appleworks 6 format first and, to be honest, the importing results can be varied.