Please show steps, i am so confused.

Sweet Acacia Corp, sells a snowboard, EZslide, that is popular with snowboard enthusiasts. Below is information relating to Sweet Acacia Corp's purchases of EZslide snowboards during September. During the same month, 104 EZslide snowboards were sold. Sweet Acacia Corp. uses a periodic inventory system. Date Explanation Units Total Cost Sept. 1 Inventory Unit Cost $110 113 $ 1,540 5,085 Sept. 12 Purchases 45 Sept. 19 Purchases 57114 6,498 Sept. 26 Purchases 115 2,760 Totals 140 $15,883 (a) Compute the ending inventory at September 30 using the FIFO, LIFO and average-cost methods. (Round average cost per unit to 3 decimal places, eg. 125.153 and final answers to decimal places, e.g. 125.) FIFO LIFO AVERAGE-COST The ending inventory at September 30 $ (b) Compute the cost of goods sold at September 30 using the FIFO, LIFO and average-cost methods. (Round average cost per unit to 3 decimal places, eg. 125.153 and final answers to 0 decimal places, e.g. 125.) FIFO LIFO AVERAGE-COST Cost of goods sold $