Please help me understand how to calculate the Cost of Goods Sold, # of units for each section... Also, not sure if I plugged things into the right place. Thanks

The beginning inventory was 330 units at a cost of $12 per unit. Goods available for sale during the year were 1,390 units at a total cost of $18,170. In May, 630 units were purchased at a total cost of $8,190. The only other purchase transaction occurred during October. Ending inventory was 595 units. Required: a. Calculate the number of units purchased in October and the cost per unit purchased in October. b. 1. Assume the periodic inventory system is used. Calculate cost of goods sold and ending inventory using FIFO method. 2. Assume the periodic inventory system is used. Calculate cost of goods sold and ending inventory using LIFO method. Complete this question by entering your answers in the tabs below. Required A Required B1 Required B2 Assume the periodic inventory system is used. Calculate cost of goods sold and ending inventory using FIFO method. Note: Enter all values as a positive value. Periodic FIFO Cost of Goods Available for Sale Cost of Goods Sold Inventory Balance Number of Cost per Cost of Goods Available for Number of Cost per Cost of Number of units Cost per Ending units unit Sale units sold unit Goods Sold in ending inventory unit Inventory Beginning Inventory 330 $ 12 $ 3,960 Purchases: May 630 13 8,190 October 430 14 6.020 595 14 8.330 Total 1,390 $ 18, 170 0 0 595 $ 8.330