Having issues with the cost of goods sold numbers

For specific identification, the March 9 sale of 80 units from beginning inventory and 340 units from the March 5 purchase; the March 29 sale consisted of units from the March 18 purchase and 120 units from the March 25 purchase. Compute gross profit earned by the company for each of the four costing methods. (Round your average cost per unit to 2 decimal places and final answers to nearest whole dollar.)