I have a one-to-many relationship defined between two tables. The parent table is represented on a form with the child table represented in a subform. I have a cost and a discount field in the child table that are shown on the subform. I have an invisible control on the subform with Control Source: =(1-[Discount])*([Cost]). The control name is "AdjustedCost". I would like the sum of all AdjustedCost controls to appear on the main form as a textbox. Is this possible? I've tried referencing queries, I've tried using DSUM, and nothing seems to give anything other than #Error and #Name?.