round down vs round out

round down and round out both are verbs.

Word	Noun	Adjective	Verb	Adverb
round down	No	No	Yes	No
round out	No	No	Yes	No

As verbs, round down and round out are synonyms defined as:

Other synonyms of round down include round, round off.

round down (verb)	round out (verb)
express as a round number	make bigger or better or more complete
	make round
	express as a round number
	fill out