please answer these right! i always get wrong answers

Required information [The following information applies to the questions displayed below.] Warnerwoods Compary uses a perpetual inventory system. It entered into the following purchases and sales transactions for March. Required: 1. Compute cost of goods avaliable for sale and the number of units available for sale. [The following information applies to the questions displayed below.] Warnerwoods Compary uses a perpetual inventory system, It entered into the following purchases and sales transactions for March. 2. Compute the number of units in ending inventory