Units from the metric system can be used to describe the mass, volume or length of an object. Mass is measured in grams (g) and kilograms (kg). Volume is measured in millilitres (ml) and litres (l).

When comparing or combining an area or volume it is important to measure the objects using the same units. Without converting the areas into the same unit, it might be difficult to tell, for example, ...

As ever more digital data is created and stored, the world needs more unit measurements to keep up with the ever-expanding numbers. To do so, the 27th General Conference on Weights and Measures on ...