Insert Column then insert designated number

It should work as posted - with the annoyance of being prompted twice for the week number. The version will only ask once. Make sure you are pasting it into a standard module and not a sheet module in the VBE.

Sub doStuff()
    Dim bRow As Long, strWeek As String, i As Integer
strWeek = Application.InputBox("Week please")
For i = 3 To 13 Step 10
With Sheets(i)
    .Rows("1:6").EntireRow.Delete
    bRow = Cells(1, 1).End(xlDown).Row
   .Rows(bRow + 1 & ":" & Rows.Count).EntireRow.Delete
    .Columns(2).Insert
   .Range("B1") = "Week"
   .Range("b2:b" & bRow) = strWeek
End With
Next
End Sub

I went back and tried it again and it still didn't work. I then went back and tried the first macro you created and it worked correctly. Could there be something in the top part of the code which identifies the Tabs to modify that could be the problem?