The problem would be PowerPoint knowing exactly how you number - There are a lot of possible variables. If the numbering is straightforward you MIGHT be able to use code like this:
Code:
Sub renum()
Dim num As Long
Dim osld As Slide
Dim oshp As Shape
num = num + 1
For Each osld In ActivePresentation.Slides
For Each oshp In osld.Shapes
If oshp.HasTextFrame Then
If oshp.TextFrame.HasText Then
If oshp.TextFrame.TextRange.ParagraphFormat.Bullet.Type = ppBulletNumbered Then
With oshp.TextFrame.TextRange
.ParagraphFormat.Bullet.StartValue = num
num = num + .Paragraphs.Count - 1
End With
End If
End If
End If
Next oshp
Next osld
End Sub
How to use code