Before measuring something, it is important to know which unit to use. Estimating its approximate size by comparing it with a more familiar object can help. In order to find a suitable unit of measure ...

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 ...