calculate vs maths

calculate is not a noun while maths is a noun.

Word	Noun	Adjective	Verb	Adverb
calculate	No	No	Yes	No
maths	Yes	No	No	No

calculate (noun)	maths (noun)
	a science (or group of related sciences) dealing with the logic of quantity and shape and arrangement

calculate (verb)	maths (verb)
make a mathematical calculation or computation
specifically design a product, event, or activity for a certain public
judge to be probable
have faith or confidence in
predict in advance
keep an account of