Sub goukei1()
   Dim math, eng, sci, soci, sum As Integer

   Range("B5").Select

   Do While ActiveCell.Value <> ""
      math = ActiveCell.Offset(0, 0).Value
      eng = ActiveCell.Offset(0, 1).Value
      sci = ActiveCell.Offset(0, 2).Value
      soci = ActiveCell.Offset(0, 3).Value
    
      sum = math + eng + sci + soci
      ActiveCell.Offset(0, 4).Value = sum
      If sum >= 320 Then
         ActiveCell.Offset(0, 5).Value = "A"
      ElseIf sum >= 280 Then
         ActiveCell.Offset(0, 5).Value = "B"
      ElseIf sum >= 240 Then
         ActiveCell.Offset(0, 5).Value = "C"
      Else
         ActiveCell.Offset(0, 5).Value = "D"
      End If
      
      ActiveCell.Offset(1, 0).Select
   Loop
End Sub
Sub goukei2()
   Dim math, eng, sci, soci As Integer

   Range("B5").Select

   Do While ActiveCell.Value <> ""
      math = ActiveCell.Offset(0, 0).Value
      eng = ActiveCell.Offset(0, 1).Value
      sci = ActiveCell.Offset(0, 2).Value
      soci = ActiveCell.Offset(0, 3).Value
    
      ActiveCell.Offset(0, 4).Value = math + eng + sci + soci
      Select Case ActiveCell.Offset(0, 4).Value
         Case Is >= 320
            ActiveCell.Offset(0, 5).Value = "A"
        Case 280 To 319
            ActiveCell.Offset(0, 5).Value = "B"
        Case 240 To 279
            ActiveCell.Offset(0, 5).Value = "C"
        Case Else
            ActiveCell.Offset(0, 5).Value = "D"
      End Select
      ActiveCell.Offset(1, 0).Select
   Loop
End Sub
Sub goukei3()
   Dim sum As Integer

   Range("B5").Select

   Do While ActiveCell.Value <> ""
      sum = 0
      For i = 0 To 3
        sum = sum + ActiveCell.Offset(0, i).Value
      Next i
      ActiveCell.Offset(0, 4).Value = sum
      If sum >= 320 Then
         ActiveCell.Offset(0, 5).Value = "A"
      ElseIf sum >= 280 Then
         ActiveCell.Offset(0, 5).Value = "B"
      ElseIf sum >= 240 Then
         ActiveCell.Offset(0, 5).Value = "C"
      Else
         ActiveCell.Offset(0, 5).Value = "D"
      End If
      ActiveCell.Offset(1, 0).Select
   Loop
End Sub