Open zip office files in Mail

[pessoa00]

I was considering buying the 3 iwork apps from Apple to be able to read and edit excel, word and powerpoint documents on the ipad that I usually receive and send via email. The problem is that most of the files I receive via Mail come zipped and I'm not sure if Pages, Numbers and Keynote will be able to open them this way and don't want to pay for the apps before I understand how this works
So the question is: will I be able to open zip files with iwork? If not, is there a turnaround?
Thanks,
António