The kilogram is the only basic unit prefixed by the international system of units, and it is also the only international unit still defined by artificial products (other units are defined by basic physical characteristics, which is convenient for different laboratories to copy). It is equivalent to how heavy a thing is, 1 kg = 1000 g, 1 kg =2 kg, 1 kg = 1 kg =20 Liang.
1. The international system of units is a consistent system of units adopted and recommended by the International Conference on Metrology (CGPM), which divides units into three categories: basic units, derived units and auxiliary units.
2. The international basic units are current (ampere), thermodynamic temperature (Kelvin), quantity (mole), length (meter), mass (kilogram), time (second) and luminous intensity (Candeira).