Creating a Price List with field notations

Apologies in advance. I know this is a very simple - But I'm struggling.

I'm trying to get the "TOTAL" field to populate with the total dollar value as you fill in all the quantities on the attached price list. I've attached the PDF so you can see what I mean. For some reason it's always coming up "0". I have the following written in the Simplified FIeld Notation: 

(QTY*PRICE) + (QTY1*PRICE1) + (QTY2*PRICE2) + (QTY3*PRICE3) + (QTY4*PRICE4) + (QTY5*PRICE5) + (QTY6*PRICE6) + (QTY7*PRICE7) + (QTY8*PRICE8) + (QTY9*PRICE9) + (QTY10*PRICE10) + (QTY11*PRICE11) + (QTY12*PRICE12) + (QTY13*PRICE13) + (QTY14*PRICE14) + (QTY15*PRICE15) + (QTY16*PRICE16) + (QTY17*PRICE17) + (QTY18*PRICE18) + (QTY19*PRICE19) + (QTY20*PRICE20) + (QTY21*PRICE21) + (QTY22*PRICE22) + (QTY23*PRICE23) + (QTY24*PRICE24).

Can anyone see where I'm going wrong? File attached