reckoning vs problem solving

reckoning and problem solving both are nouns.

Word	Noun	Adjective	Verb	Adverb
reckoning	Yes	No	No	No
problem solving	Yes	No	No	No

As nouns, problem solving is a hypernym of reckoning; that is, problem solving is a word with a broader meaning than reckoning:

reckoning (noun)	problem solving (noun)
the act of counting; reciting numbers in ascending order	the thought processes involved in solving a problem
problem solving that involves numbers or quantities	the area of cognitive psychology that studies the processes involved in solving problems
a bill for an amount due