sum vs totality

sum and totality both are nouns.

Word	Noun	Adjective	Verb	Adverb
sum	Yes	No	Yes	No
totality	Yes	No	No	No

As nouns, sum and totality are synonyms defined as:

Other synonyms of sum include aggregate, total.

sum (noun)	totality (noun)
the whole amount	the whole amount
the choicest or most essential or most vital part of some idea or experience	the quality of being complete and indiscriminate
a quantity obtained by the addition of a group of numbers	the state of being total and complete
the final aggregate
a set containing all and only the members of two or more given sets
a quantity of money

sum (verb)	totality (verb)
determine the sum of
be a summary of