mpute the ending inventory at May 31 and cost of goods sold using the FIFO, LIFO, and average-cost methods. (Round per unit st to 3 decimal places, e.8. 15.647 and final answers to 0 decimal places, e.g. 5,125.) mpute the ending inventory at May 31 and cost of goods sold using the FIFO, LIFO, and average-cost methods. (Round per unit st to 3 decimal places, e.8. 15.647 and final answers to 0 decimal places, e.g. 5,125.)