In page break preview, a big number identifies the page.
When a worksheet prints on several pages, Excel inserts automatic page breaks that divide the worksheet into separate pages for printing. These page breaks appear as dotted lines, which you can see by looking at the worksheet in page break preview. You can control what appears on a page by changing those page breaks or creating your own.
To do that, in print preview, click Page Break Preview (or in normal view, click Page Break Preview on the View menu).
For example, on the page shown in the picture, if you wanted to print the page without that last column on the right, you could create a page break as shown, to push that column onto another page.
The page breaks that Excel inserts are dashed lines. To change page breaks, you drag them. For example, to create a page without the last column, as shown in the picture, you would drag the dotted line to the left. Once moved, that dotted line becomes a manual page break, and changes to a solid line.
Or you could select the last column, right-click, and then click Insert Page Break.
If you don't like the page breaks you create, right-click the worksheet and select Reset All Page Breaks. Or you can remove a page break by dragging it outside the print area.
Note Be sure to preview your worksheet after you create or change page breaks, because they can change other settings, such as the Fit to option.