What is the difference between atomic mass, relative atomic mass and average atomic mass

Difference between Atomic mass, relative atomic mass and average atomic mass :-

Atomic Mass :-Atomic mass is the mass of neutrons and protons present in the nucleus of an atom .It is always calculated for a single element and having direct value For isotopes also, the atomic mass is calculated separately . Example :- Carbon 12 , carbon 13 and carbon 14 have different atomic mass. The SI unit of Atomic mass is " u" and "amu"Relative Atomic mass :-Relative atomic mass is mean mass of the atoms of an element which is compared to the 1/12th mass of carbon - 12 .Carbon - 12 is taken as a relative when we calculate the relative atomic mass of any element For calculating relative atomic mass, we need to know the masses, percentage and abundance of all types of elements Relative atomic mass is a dimension less quantity Average Atomic Mass :-Average atomic mass is the average mass of an atoms of a particular element by considering it's isotopes While we calculate average atomic mass is a standardized number. Whereas, Average atomic mass sometimes varies geologically .It also includes percentage, abundance and masses of given element .In average atomic mass, We do not compare mean value with the 1/12 mass of carbon - 12The unit of Average atomic mass is "Amu" or " u " .