It’s sometimes hard to understand a teenager. It’s even harder if a teenager doesn’t agree with you .
Listen to what the teenager has to say.    While you may not entirely agree with what he’s saying, the tension will be lessened if the teenager feels like you are listening and trying to understand him. Also, he might return the favor and give you the chance to talk as well. It’s best to have a conversation where both of your opinions matter rather than fight and possibly hurt each other in the process.
Understand that while teenager may appear grown up and perhaps even sound matured, his mind has not fully developed, and he cannot think like an adult all the time.    However, this doesn’t mean you’re completely right or he deserves to be ridiculed or treated like a child.
  However, remember that the teenager should understand when “no” is “no”. Avoid bringing up a compromise every time you disagree on something. This might teach him that he can always get away with what he wants ,whenever he wants it.
If the conversation launches into an argument, stop it. Tell him that you both need to calm down and think clearly or the problem will never be solved. If he refuses to listen to you and continues arguing , step out of the room and allow time for both of you to settle down. Do not scold him or shout back. Your words will possibly be lost on the teenager since you both are too angry to listen to each other.   He still needs to learn, and he doesn’t know everything.

A．Avoid having a bad tone, including accusations in your words.

B．This article tells you how to disagree with a teenager in a kind manner.

C．Bring up the topic after a while and make sure you listen to each other patiently.

D．People like being listened to, so give him the chance to express his opinion.

E.Come up with a compromise if the situation allows one.
F.Find the good points the teenager has and mention the negative points as well.