A fun and interactive quiz to master unit conversions. This tool uses a built-in library of common units for length, volume, and mass, with no external lookups. It generates questions randomly, asking users to convert between units (e.g., meters to kilometers, liters to milliliters). The quiz is timed, offers multiple-choice answers to guide learning, and provides instant feedback and a final score. It's a great way to practice and solidify understanding of the metric system.