tally vs summate

tally is a noun but summate is not a noun.

Word	Noun	Adjective	Verb	Adverb
tally	Yes	No	Yes	No
summate	No	No	Yes	No

As verbs, tally and summate are synonyms defined as:

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

tally (noun)	summate (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)	summate (verb)
determine the sum of	determine the sum of
keep score, as in games	form or constitute a cumulative effect
gain points in a game
be compatible, similar or consistent; coincide in their characteristics