Private Sub hoge()

Range("a1").Value = 40.123
Range("b1").Value = 20.1
Range("c1").Value = Range("A1").Value & "〜" & Range("B1").Value

Range("c2").Value = Format(Range("A1").Value, "###.0") & "〜" & Format(Range("B1").Value, "###.0")

End Sub