In the international system of units, kilogram is the basic unit of mass, while kilogram is the traditional unit of mass. The conversion relationship between them is 1kg = 2kg. So 1.38 kg can be converted into kg by simple calculation, that is, 1.38 kg/1 kg *2 kg/1 kg =2.76 kg.
Unit refers to the name of the standard quantity used to measure things in mathematics or physics.