Note though that will generate a number between 1 and 12.
To get what you said you would need to pass the High and the Low values
Code:
Sub UpdateRandomNumber(oSh As Shape)
oSh.TextFrame.TextRange.Text = CStr(Random(100, 25))
SlideShowWindows(1).View.GotoSlide (SlideShowWindows(1).View.Slide.SlideIndex)
End Sub
Function Random(High As Long, Low As Long) As Long
Randomize
Random = Int((High - (Low - 1)) * Rnd) + Low
End Function