Reyginus:
I don't see anything too intelligent in the question as some are trying to make it appear. You don't know one's debt of anything by asking the wrong questions. Answering one is not any way intelligent.

If the interviewer expected two as answer or a response emphasizing the base or association then it's okay. Maybe to ascertain how you handle unexpected questions. If what he or she expects is not that then it's useless and irrational. There's nothing intelligent at this point.

I tire o My brother.... The interviewer was looking for pragmatic answer which was at that time, so difficult to give. In any job interview, boldness and simplicity matters, don't try to impress cos it might hit you in the process. We all know that the conventional answer is 2 and the Plus(+) sign had made it so. Why not just answer 2 and let what will follow, have its way. So what's that dude Rapping base1 and 2 for? Abeg free the Over Sabi....

Elythron16zero4:
so if the interviewer had asked what is your name, the response should be the name i bear. Hmm
it's only good everybody is entitled to his/her opinion. But on the contrary this question expects 2 as an answer but i think the interviewer is trying to work on the psyche of the interviewee. Once i asked an sss 3 student to spell hen and he couldn't believe i would ask him something as simple as that in a dictation and he wrote something else but i wanted hen as an answer.
I think that is it but everyone keep thinking it's technical it's a lie. If a company wants to know how you will add value to them they simply come straight or indirectly ask you why should we hire you?
most comments on the technicality of the question are mere conjectures.

sir can you differentiate these questions A: 1+1? B: 1+1= C: what is 1+1

waoow... I can see alot of diffrnt answers but in my own opinion it iz a straight forward question wt a direct answer, the question says wat is 1+1? And the answer is addition.

@op its a very simple question. incase you are asked by any interviewer, all you have to say is that, 1+1 can be anything sir. you will now ask him Sir, what do you want your 1+1 to be. that is the answer folks and you will get a call back for the interview. If he says I want it to be 3 you can tell him you will work with your team to find a way to deliver three times what two people can offer. if he says let your 1+1 be 4. tell him it will take a lot of hard work and persistence tp get that result but its possible with the right team

paranorman:
This is really a logical one.
If I were in his shoes I'd give two answers, thus:
logically, in Mathematics, depending on the base system, 1+1 is two calculating in base 10.
On the brighter side, I think 1 + 1 is 1. Every organization need to have employees working towards a common goal, which requires cooperations, innovations, shatring ideas e.t.c. In this context, team work cannot be over- or under-emphasized. Many sticks make a broom. Therefore, 1 + 1 is one!

wa gbayi omo Iya.

Favparis:
only for the intellects.......

I initially wanted to read through and go, But No!!! This is for intellects!!! I am an intellect!!! The answer is ...... I dey come jawe