approximation vs calculation

approximation and calculation both are nouns.

Word	Noun	Adjective	Verb	Adverb
approximation	Yes	No	No	No
calculation	Yes	No	No	No

As nouns, calculation is a hypernym of approximation; that is, calculation is a word with a broader meaning than approximation:

Other hypernyms of approximation include computation, figuring, reckoning.

approximation (noun)	calculation (noun)
the act of bringing near or bringing together especially the cut edges of tissue	the procedure of calculating; determining something by mathematical or logical methods
the quality of coming near to identity (especially close in quantity)	problem solving that involves numbers or quantities
an approximate calculation of quantity or degree or worth	planning something carefully and intentionally
an imprecise or incomplete account