add together vs tally

add together is not a noun while tally is a noun.

Word	Noun	Adjective	Verb	Adverb
add together	No	No	Yes	No
tally	Yes	No	Yes	No

As verbs, add together and tally are synonyms defined as:

Other synonyms of add together include add, add up, sum, sum up, summate, tot, tot up, total, tote up.

add together (noun)	tally (noun)
	the act of counting; reciting numbers in ascending order
	a score in baseball made by a runner touching all four bases safely
	a bill for an amount due

add together (verb)	tally (verb)
make an addition by combining numbers	determine the sum of
determine the sum of	keep score, as in games
	gain points in a game
	be compatible, similar or consistent; coincide in their characteristics