Will someone show me how to exactly workout costs of goods sold and gross profit?

Assume that Mitchell Company uses a periodic inventory system and has these account balances: Purchases $620,000 Purchase Returns and Allowances $25,000 Purchases Discounts $11,000 Freight-ln $19,000 Beginning inventory of $45,000 Ending inventory of $55,000 Net sales of $750,000 Determine the amounts to be reported for cost of goods sold and gross profit Calculation of cost of goods sold Cost of goods sold Less: Purchases returns and allowances $45,000 $620,000 ....$25,000 11,000 36.000 584,000 Purchase discounts 19,000 Cost of goods purchased Cost of goods available for sale........................... Inventory, ending Cost of goods sold 603,000 648,000 55,000 Calculation of gross profit $750,000 593,000