FirstSlideNumber Property Example
This example shows how changing the first slide number in the active presentation affects the slide number of a specific slide.
With Application.ActivePresentation
.PageSetup.FirstSlideNumber = 1 'starts slide numbering at 1
MsgBox .Slides(2).SlideNumber 'returns 2
.PageSetup.FirstSlideNumber = 10 'starts slide numbering at 10
MsgBox .Slides(2).SlideNumber 'returns 11
End With