noun as adjective

When using a descriptive noun as an adjective, such as a method that uses 3 cups for something, is it written as the 3-cup method or the 3-cups method?

[Casiopea]

Originally Posted by Unregistered

When using a descriptive noun as an adjective, such as a method that uses 3 cups for something, is it written as the 3-cup method or the 3-cups method?

With units of measure, e.g., millimeter, cup, million, percent, and so on, do not use a hyphen:

5 millimeters
3 cups
3.5 million people
15 percent