I have a column in one spreadsheet (Call it "Orders") into which I enter a
book name that I sell, a second column into which I enter a quantity, and a
third column into which the price is entered by looking up the book and
quantity in a different spreadsheet (call it "Pricing") in a different file,
finding the book's price, multiplying the quantity by the price, and
inserting that into the cell containing the lookup function. I don't know how
to write that formula and would appreciate help.