Please explain BOTH PARTS of the question. Thank you!

Vaughn Inc. is a retailer operating in British Columbia. Vaughn uses the perpetual inventory system. All sales returns from customers result in the goods being returned to inventory; the inventory is not damaged. Assume that there are no credit transactions; all amounts are settled in cash. You are provided with the following information for Vaughn Inc. for the month of January 2022. Calculate the Moving-average cost per unit at January 1,5, 8, 10,15,16, 20, \& 25. (Round moving-average cost per unit answers to 3 decimal places, e.g. 5.251.) For each of the following cost flow assumptions, calculate cost of goods sold, ending inventory, and gross profit. (1) LIFO. (2) FIFO. (3) Moving-average cost. (Round average-cost per unit to 3 decimal places, e.g. 12.502 and final answer to 0 decimal places, e.g. 1,250.)