As a teacher, if you were asked a question from a student in the class which you don't know the answer for. What is the smartest thing to do?

ok when a student asks such question which even teacher doesnt know, its better to drag that question to the entire class as a homework ,it will shiw how much they were into class lecture and also it will enhance their curiosity towards searching.

 Drag that question to the sub class as a homework .

I will not say that, I don't know the answer" but I will say good question and let me think about it and we will discuss later

First appreciate the question and then let the class students to answer same question. In this way you can divert the pressure to class mates, may also figure out the correct answer.

Students are curious and smart enough to understand, whether the teacher knew the answer or just diverting. The smartest thing to do is "That's good question, but you're not the first to ask. Many students asked this question in several insitutions. It'll wise to first visit our library and gather relevant information on this topic. If you still get it, please approach me". You can even refer some author. 

First thing is to appreciate and praise the student for presenting such a challenging question. Then state as a matter of fact that it needs some thinking and additional preparation on the part of the teacher to give an answer which is correct from all angles. Then express a clear time by which teacher would provide the answer to the student and the rest of the class.

Personally, after I reverted to with a well-researched answer, I had awarded a bonus point to students who could ask such question and started a competition in the class for more such questions to win bonus points.

Not only it ended up being a more effective learning experience for them, they also liked the honesty and that is class where I still have the most connection with.

Let's google it here togather and now.

First, I would think about the question to see if I know anything on the subject while acknowledging the question and the student. Second, I would address it to the class to see if any of the other students may know the answer. Lastly, I would assign it as a homework assignment for the class and myself to see what different answer we would come up with. This would not only broaden my scope of the question but my students as well. This could be a teachable moment to show my students that even teacher do not know all the answer but are willing to do the research to find the correct answer.

each one of us has his own thinking; moreovere you do not know everything ,and if you were asked about a student a question that you don't know its answern you can tell him that you'll seek informations about his question and tell him later ,not to lie to him and even you don't know the answer and if you do you may be asked the same question from another student ,so in this this case what to do? so my advice is  search, learn and teach.

 

I will ask th student whether he knows the answer. Whether Yes / No the answer it does not matter. Will ask the class anybody knows the answer. If somebody says, I will appreciate both students. If nobody knows the answer except the particular student who asked the question, he will be given the chance to explain to the class and he will be appreciated and motivated. If nobody knows tha answer, it may be given as a homework and before coming to the next class, I will seek my pears support to solve the question.

tell them to look it up and next time you will discuss it with them