For Each a In Array("M", "P", "U", "X", "AC", "AF", "AK", "AN", "AS", "AV", "AZ")
    With ThisWorkbook.Sheets("Agent_View")
        For i = 18 To 47
             With .Cells(i, a)
                If IsNumeric(.Value2) Then
                    Select Case .Value2
                    Case Is <= 200: .Interior.ColorIndex = 43
                    Case Is <= 250: .Interior.ColorIndex = 44
                    Case Is >= 251: .Interior.ColorIndex = 3
                    End Select
                Else
                    Cells(i, a).Interior.ColorIndex = 0
                End If
            End With
        Next i
    End With
    Next a

I have this code but it doesnt work the way I need it to , can anyone assit, if column az18 is
<=200 then a18:h18 = .Interior.ColorIndex = 43
<= 250 then a18:h18 = .Interior.ColorIndex = 44
>= 251: then a18:h18 = .Interior.ColorIndex = 3

then do the same with az19 all the way to az47

can anyone help ?