computation vs reckoning

computation and reckoning both are nouns.

Word	Noun	Adjective	Verb	Adverb
computation	Yes	No	No	No
reckoning	Yes	No	No	No

As nouns, computation and reckoning are synonyms defined as:

computation and reckoning: problem solving that involves numbers or quantities

Other synonyms of computation include calculation, figuring.

computation (noun)	reckoning (noun)
the procedure of calculating; determining something by mathematical or logical methods	the act of counting; reciting numbers in ascending order
problem solving that involves numbers or quantities	problem solving that involves numbers or quantities
	a bill for an amount due