While working on your QuarkXPress document, you can keep the document palette opened (VIEW-> SHOW DOCUMENT LAYOUT)
when you magnify your document, there is a small highlight in the document layout which shows which page you are currently on. So even if you have a small portion of first page and a small portion of the second page on the screen at the sametime, now if u press ctrl+0 depending on which page is highlighted in the documant layout palette it will be dispalyed...