operand vs quantity

operand and quantity both are nouns.

Word	Noun	Adjective	Verb	Adverb
operand	Yes	No	No	No
quantity	Yes	No	No	No

As nouns, quantity is a hypernym of operand; that is, quantity is a word with a broader meaning than operand:

operand: a quantity upon which a mathematical operation is performed
quantity: the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable

operand (noun)	quantity (noun)
a quantity upon which a mathematical operation is performed	how much there is or how many there are of something that you can quantify
	an adequate or large amount
	the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable