I plugged that in and couldn't get it to work.

As a reminder I want to set the value of column K equal to the value of column A x column J. All the values in Column K are summed and added to shipping and tax to give the value of Total. 
Sub PO_CalcTotal()
Range("K15").Select
    ActiveCell.FormulaR1C1 = "=RC[-1]*RC[-10]"
    Range("K15").Select
    Selection.AutoFill Destination:=Range("K15:K18"), Type:=xlFillDefault
    Range("K15:K18").Select
    ActiveWindow.SmallScroll Down:=6
    Range("K21").Select
    ActiveCell.FormulaR1C1 = "=SUM(R[-6]C:R[-3]C)+R[-2]C+R[-1]C"
    Range("F22:K22").Select
    ActiveWindow.SmallScroll Down:=-18
End Sub
What do you think is wrong? Thanks!