Skysong, Inc. uses a periodic inventory system and reports the following for the month of June.

Date		Explanation		Units			Unit Cost			Total Cost
June 1		Inventory		130			$5			$ 650
12		Purchase		390			6			2,340
23		Purchase		220			7			1,540
30		Inventory		224

Compute the cost of the ending inventory and the cost of goods sold under FIFO, LIFO, and average cost. (Round per unit cost to 3 decimal places, e.g. 15.647, and final answers to 0 decimal places, e.g. 5,125.)

		FIFO		LIFO		Average-cost
Cost of the ending inventory
Cost of goods sold

Could you explain how to tackle this kind of problem, I'm struggling to understand how to do this.