Duvidas com formulas / Questions about formulas

[budhaaf]

Hello I would like help with formulas, I don’t know where to start

I have in my bank, the price of pieces (X) and quantity of pieces (y). I need to find out the billing of each order. For that I need to multiply x * y =z in each record and add it to all the records displayed in the list sector

[budhaaf]

The way I’ve been doing this is going wrong by multiplying the sum of the entire list by the sum of the value of parts.
I need to do the multiplication between x*y =z first dps add all the z