Office 2013 combines cloud and web technologies to extend the way you create and consume information, and introduces a new cloud app model for you to build secure and flexible apps—all discoverable from the familiar Office interface.
To earn a Microsoft Office 2013 Expert certification, you must pass both of the MOS Expert required exams listed:
MOS: Microsoft Office Word 2013 Expert
425 and 426
MOS: Microsoft Office Excel 2013 Expert
427 and 428