Excel to PDF

Click "save as" and go to where you want to save the file.

In the save as window, underneath where you will type in the file name, it will say "Save as type"

Click the drop down arrow for "save as type" and scroll down until you see PDF.

Outstanding! I had no idea you could do that.

Yep.

You can also save one or multiple PowerPoint slides as jpgs, pngs, gifs, etc.

I'm not just another pretty face.

Alternatively (at least this works with Excel in Microsoft Office Starter, I don't have the proper Microsoft Office):

In the "File" menu, choose "Print". Where it says "Printer", click on the little triangle on the right and select "Microsoft Print to PDF". There are also "Settings" options underneath where you can set the page size (which seems to be set by default to "Letter") to A3.

Cool!

There's always more than one way to do something.

Select excel spreadsheet you want to save.
Go to "file" tab. click on "Create PDF", and save it.