I'm looking for a single-word adjective which means 'satisfies the given conditions'. For example, the condition might be, "Your number must be less than 10." Here the number 2 would be a _____ number. This is specifically in a mathematical context so the surrounding language is somewhat formal.
I thought of satisfactory (but it sounds like I'm still not happy with the choice), suitable (I've used this word once already so I don't want to repeat it), and fitting (doesn't really... fit).