Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
Dim s$, v%, k%
With Target
If .CountLarge > 1 Then Exit Sub
If .Column <> 1 Then Exit Sub
s = .Value: v = Val(s): If v < 1 Or v > 9 Then Exit Sub
s = Right$(s, 1): .Font.Size = 12 - (s = "b") * 6
k = 9311 - (s = "n") * 790 - (s = "b") * 810 + v
Application.EnableEvents = 0
.Value = Evaluate("=UNICHAR(" & k & ")")
Application.EnableEvents = -1
End With
End Sub