How to unhide and unhide certain column based on cell value

White_fang_of_leaf 

I assume that columns A to D, or at least column B, should remain visible (if you hide column B, you cannot change B2).

Right-click the sheet tab.

Select View Code from the context menu.

Copy the code listed below into the worksheet module.

Switch back to Excel.

Save the workbook as a macro-enabled workbook (*.xlsm).

Make sure that you allow macros when you open the workbook.

Private Sub Worksheet_Change(ByVal Target As Range)
    If Not Intersect(Range("B2"), Target) Is Nothing Then
        Application.ScreenUpdating = False
        Range("E1:XFD1").EntireColumn.Hidden = True
        Select Case Range("B2").Value
            Case 1
                Range("E1:H1").EntireColumn.Hidden = False
            Case 2
                Range("I1:L1").EntireColumn.Hidden = False
            Case 3
                Range("M1:O1").EntireColumn.Hidden = False
        End Select
        Application.ScreenUpdating = True
    End If
End Sub