As we mentioned earlier, if two or more adjectives provide separate descriptions of the noun or pronoun, they are called consecutive adjectives. Because they do not act as a single unit to provide just one description of the noun, they are not joined into a single unit with hyphens. Instead, they are separated with a comma.
As you learned earlier, an easy way to decide whether you should put a comma between two adjectives is to separate the adjectives with the word and. If the word and makes sense, and sounds right to you, put a comma between the adjectives. Of course, you can leave the and between them if you want; in that case, you should leave the comma out.
"New and inexpensive information appliance" sounds right, so we should put a comma between new and inexpensive:
"Adjusted and gross income" does not sound right,
so we should not put a comma between adjusted and