tally vs tot up

tally is a noun but tot up is not a noun.

Word	Noun	Adjective	Verb	Adverb
tally	Yes	No	Yes	No
tot up	No	No	Yes	No

As verbs, tally and tot up are synonyms defined as:

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

tally (noun)	tot up (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

tally (verb)	tot up (verb)
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