Compound Sum Or Subtotals

Have a look at the attache example. I have inventory items which have a fixed value. I have several quantity columns to reflect various inventory positions. (OnOrder, WIP, ATP, ATS, OnHand, PAB as at date()...)

At the top of the sheet I need to show sum of quantities and sum of values. In order to compute the values currently I need to hide columns to the extreme right to do the math on a row by row level and then sum the rows and copy the the value to another cell. In this case the cells with yellow background.

Is there a way to be able to write a formula that would return the sum of the qty multiplied by the value without adding an additional column. I would need to function like with filters as well (like =subtotal())