number crunching vs calculation

number crunching and calculation both are nouns.

Word	Noun	Adjective	Verb	Adverb
number crunching	Yes	No	No	No
calculation	Yes	No	No	No

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

number crunching: performing complex and lengthy numerical calculations
calculation: the procedure of calculating; determining something by mathematical or logical methods

Other hypernyms of number crunching include computation, computing.

number crunching (noun)	calculation (noun)
performing complex and lengthy numerical calculations	the procedure of calculating; determining something by mathematical or logical methods
	problem solving that involves numbers or quantities
	planning something carefully and intentionally