Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Target, [A1]) Is Nothing And Target.Count = 1 Then
Select Case [A1]
Case 1000000 To 1000100, 2000000 To 2000100, 3000000 To 3000100, 4000000 To 4000100, 5000000 To 5000100
[B1].Interior.ColorIndex = 3
Case Else
[B1].Interior.ColorIndex = 0
End Select
End If
End Sub