Percentages are ratios expressed as a fraction of 100. They are used commonly to represent things like discounts, interest rates, and exam scores. Examples are given to demonstrate how to calculate percentages of different amounts. Specifically, 100% means all, 50% means half, and 3.5% means 3.5/100. Charts can also help visualize percentages and compare amounts spent on different items from a total amount. Understanding percentages is important for real-life applications like discounts, loans, investments, and exam results.