In this lesson, students in the ninth year will learn about different stock rotation methods, specifically focusing on retail products sold in stores. Key terms discussed include FIFO (First In, First Out), which refers to selling the oldest stock first, thereby minimizing waste from expired products. The lesson emphasizes the importance of efficient stock rotation to ensure that perishable items, like food and drinks, are sold before their expiration dates. Students will also distinguish between FIFO and FEFO (First Expired, First Out), which focuses on selling items based on their expiration dates.