help!! I have written a Purchase Order System and have now reached the stage of debugging. Even though this system went "live" a couple of months ago, one (Of many) problems remain. The Most important fields I have are: "QTY", "Description", "Cost" (per unit). The QTY & COST fields calculate fine ([QTY]*[Cost]), but as there are 22 lines for our PO's each field needs to be calculated to produce a final total. Is there a way of setting the default values of QTY & COST to 0 then use a mask to hide any zero value, but still calculate it on the Order Cost???