What is keyboard shortcut to cycle through worksheets in excel (office 2011) workbook on mackbook air? It looks like the shortcut is listed as Command+PageDown, but there's no "page down" on a mackbook air.  how can I cycle through the tabs (worksheets) in an excel workbook?
According to Apple's Mac notebooks: Key placement and functions:


  Page Up key functionality is performed by pressing Fn and Up Arrow key.
  
  Page Down key functionality is performed by pressing Fn and Down Arrow key.