PA7-1 (Algo) Analyzing the Effects of Four Alternative Inventory Methods in a Periodic Inventory System [LO 7-3] Gladstone Company tracks the number of units purchased and sold throughout each accounting period but applies its inventory costing method at the end of each period, as if it uses a periodic inventory system. Assume its accounting records provided the following information at the end of the annual accounting period, December 31. Transactions Units Unit Cost Beginning inventory, January 1 1,500