Mass is measured with a scale. Like all measuring instruments, scales express units. These units can be divided into smaller units, and they are themselves subdivisions of larger units.
In the metric system, the divisions are based on multiples of 10. For example, there are 10 grams in a dekagram, 10 dekagrams in a hectogram, and 10 hectograms in a kilogram. The British system is a bit more complex. For example, in the British system, 16 ounces make up one pound, and 2000 pounds make up one ton. Each unit in each system has a unique symbol.
Let's play a game to help you learn the names of the mass units in the British and metric systems and their symbols.