Returns or sets the slide number for the first slide in the presentation. Read/write Long.
Remarks
The slide number is the actual number that will appear in the lower-right corner of the slide when you display slide numbers. This number is determined by the number (order) of the slide within the presentation (the SlideIndex property value) and the starting slide number for the presentation (the FirstSlideNumber property value). The slide number will always be equal to the starting slide number + the slide index number – 1. The SlideNumber property returns the slide number.