I need help figuring this out. This is so confusing to me. Please provide step by step on how I calculate this please and thank you.

Penn Company uses a periodic inventory system. At the end of the annual accounting period, December 31, 2015, the accounting records provided the following information for product 1:

	Units	Unit Cost
Inventory, December 31, 2014	2,000		$	4
For the year 2015:
Purchase, March 21	5,010			6
Purchase, August 1	2,880			7
Inventory, December 31, 2015	4,030

Required:

Compute ending inventory and cost of goods sold under FIFO, LIFO, and average cost inventory costing methods.(Round "Average cost per unit" to 2 decimal places and final answers to nearest whole dollar amount.)