The math topic focuses on calculating the percent change when a number decreases, specifically working with 10% increments. Students identify discounts in various transactions, such as paying a reduced price for an item originally priced higher. Each problem presents an initial price and a discounted price, and students calculate the percentage discount. Multiple-choice answers are provided to allow students to select the correct discount percent. The problems are visualized with images, and this topic is an introductory part of a larger unit on percentages.