The document discusses the metric system of measurement. It explains that the metric system is based around units of 10, with prefixes denoting multiples and fractions of the base units. The three main units are meters for length, liters for liquid volume, and kilograms for mass. Meters are slightly longer than yards, liters slightly more than quarts, and kilograms slightly more than 2 pounds. The metric system is gaining global adoption for its simplicity compared to other systems like the English/U.S. customary units.