I'm trying to sort out an editable pdf form, where from a drop down menu one can select the number of delegates from 3 different categories, with different costs e.g. Member, non-member and retired member. I then want the total cost to be automatically calculated. I can get it to add up how many delegates there are in total, but I can't see how I can multiply each individual delegate category by the cost and then sum the 3 different totals. Ta.