Sub Demo()
Application.ScreenUpdating = False
With ActiveDocument.Range
  With .Find
    .ClearFormatting
    .Replacement.ClearFormatting
    .Text = "[0-9]@>"
    .Font.Superscript = True
    .Replacement.Text = ""
    .Format = True
    .Forward = True
    .Wrap = wdFindStop
    .MatchWildcards = True
    .Execute
  End With
  Do While .Find.Found
    If .Text = "0" Then
      .Text = CLng(.Text + 1)
      i = 1
    Else
      .Text = CLng(i + 1)
      i = i + 1
      .Collapse wdCollapseEnd
      .Find.Execute
    End If
  Loop
End With
Application.ScreenUpdating = True
End Sub