subtract vs cut down

subtract and cut down both are verbs.

Word	Noun	Adjective	Verb	Adverb
subtract	No	No	Yes	No
cut down	No	No	Yes	No

As verbs, cut down is a hypernym of subtract; that is, cut down is a word with a broader meaning than subtract:

Other hypernyms of subtract include bring down, cut, cut back, reduce, trim, trim back, trim down.

subtract (verb)	cut down (verb)
take off or away	cut down on; make a reduction in
make a subtraction	intercept (a player)
	cause to come or go down
	cut with a blade or mower
	cause to fall by or as if by delivering a blow
	cut with sweeping strokes; as with an ax or machete