Inventory Using FIFO, LIFO, and Weighted Average Cost Methods The units of an item available for sale during the year were as follows: There are 14 units of the item in the physical inventory at December 31. The periodic inventory system is used. Determine the inventory cost using the first-in, first-out (FIFO) method; the last-in, first-out (LIFO) method; and the weighted average cost method. First-in, first-out (FIFO) method Last-in, first-out (LIFO) method Weighted average cost method