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, ...

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 I need a quick calculation, I fire up the Mac calculator, get it done, and don’t think about it much. But for complex calculations such as currency conversations or splitting bills, I reach for a ...