help me figure out whats wrong with this problem please!!!

Hemming uses a periodic inventory system. Ending inventory consists of 50 units from the March 14 purchase, 80 units from the July 30 purchase, and all 155 units from the October 26 purchase. Using the specific identification method, calculate the following. a) Cost of Goods Sold using Specific Identification Available for Sale Date January 11 March 14 July 30 October 26 Activity Less: Equals: Beginning Inventory Purchase Purchase Purchase # of units b) Gross Margin using Specific Identification Sales Cost of goods sold Gross profit 255 410 455 155 1,275 $41,580 17,628 $23,952 Cost Per Unit $ 12.20 $ 17.20 $ 22.20 $ 27.20 Answer is complete but not entirely correct. # of units sold 255 360 375 0 990 Cost of Goods Sold Cost Per Unit $ $ $ s 12.20 17.20 22.20 27.20 COGS $ 3,111 6,192 8,325 0 $ 17,628 Ending Inventory Units Ending Inventory Cost Per Unit 00 $ 50 $ 80 $ 155 $ 285 12.20 17.20 22.20 27.20 Ending Inventory Cost+ S 0 860 1,776 4,216 6,852 $ Required information [The following information applies to the questions displayed below.] Hemming Company reported the following current-year purchases and sales for its only product. Date January 11 January 10 March 14 March 15 July 30 October 5 October 26 Activities Beginning inventory Sales Purchase Sales Purchase Sales Purchase. Totals Units Acquired at Cost $12.20- e $17.20 = @ $22.20 - 255 units 410 units 455 units 155 units 1,275 units @ $27.20 $ 3,111 7,052 10,101 4,216 $ 24,480 Units Sold at Retail 210 units 350 units 430 units 990 units e $42.20 e $42.20 e $42.20