add up vs amount

add up is not a noun while amount is a noun.

Word	Noun	Adjective	Verb	Adverb
add up	No	No	Yes	No
amount	Yes	No	Yes	No

As verbs, add up and amount are synonyms defined as:

Other synonyms of add up include come.

As verbs, add up and amount are synonyms defined as:

Other synonyms of add up include come, number, total.

add up (noun)	amount (noun)
	how much there is or how many there are of something that you can quantify
	the relative magnitude of something with reference to a criterion
	a quantity obtained by the addition of a group of numbers
	a quantity of money

add up (verb)	amount (verb)
determine the sum of	to measure up to in kind or quality
be reasonable or logical or comprehensible	add up in number or quantity
to measure up to in kind or quality	be tantamount or equivalent to
add up in number or quantity