Hi, I got most of these answers wrong on my homework and I was wondering what I'm doing wrong. I got both the LIFO questions right but all the others wrong.

Periodic inventory by three methods; cost of goods sold

The units of an item available for sale during the year were as follows:

Jan. 1	Inventory	30 units at $118
Mar. 10	Purchase	70 units at $130
Aug. 30	Purchase	30 units at $134
Dec. 12	Purchase	70 units at $138

There are 80 units of the item in the physical inventory at December 31. The periodic inventory system is used.

Determine the ending inventory cost and the cost of goods sold by three methods. Round interim calculations to one decimal and final answers to the nearest whole dollar.

Cost of Ending Inventory and Cost of Goods Sold
Inventory Method	Ending Inventory	Cost of Goods Sold
First-in, first-out (FIFO)	$13680	$12640
Last-in, first-out (LIFO)	$10040	$16280
Weighted average cost	$15792	$10528