What's the best way to solve for the following step by step? I'm having a particularly hard time calculating LIFO's COGS?

Hamilton Company uses a periodic inventory system. At the end of the annual accounting period, December 31 of the current year, the accounting records provided the following information for product 1: Units Unit Cost Inventory, December 31, prior year For the current year 1,890 $8 6,180 4,110 2,890 7 Purchase, March 21 Purchase, August 1 Inventory, December 31, current year Required Compute ending inventory and cost of goods sold under FIFO, LIFO, and average cost inventory costing methods. (Round Average cost per unit" to 4 decimal places and final answers to nearest whole dollar amount.) Average Cost FIFO LIFO 4,450 S 22,120 Ending inventory $ Cost of goods sold64,480