Can someone please help me understand how to calculate "less: ending merchandise inventory and cost of goods sold?"

10A. Happy Books has the following transactions in August related to merchandise inventory. i (Click the icon to view the transactions.) a. Determine the cost of goods sold and ending merchandise inventory using the FIFO inventory costing method assuming Happy Books uses the periodic inventory system. Determine the cost of goods sold and ending merchandise inventory using the LIFO inventory costing method assuming Happy Books uses the periodic inventory system. c. Determine the cost of goods sold and ending merchandise inventory using the weighted average inventory costing method assuming Happy Books uses the periodic inventory system. b. a., b., and c. Determine the cost of goods sold and ending merchandise inventory using the (a) FIFO inventory costing method, (b) LIFO inventory costing method, and (c) weighted-average inventory costin method assuming Happy Books uses the periodic inventory system. (Round weighted average cost per unit to the nearest cent and all other amounts to the nearest dollar.) a. FIFO More Info Beginning merchandise inventory 352 Plus: 414 Net cost of purchases Cost of goods available for sale 766 Less: Ending merchandise inventory 7 Aug. 1 Beginning merchandise inventory, 16 books @ $22 each 3 Sold 4 books @ $17 each 12 Purchased 15 books @ $24 each 15 Sold 15 books @ $17 each 20 Purchased 2 books @ $27 each 28 Sold 8 books @ $23 each Cost of goods sold Print Done