you are able to speak confidently on them if you are fresher then interviewer does not expect you will answer very complex questionsrather you have to make your basics concepts very strong second it really doesn' matter much if you could not answer few questions but it matters that whatever you answeredyou must have answered with confidence so just feel confident during your interview we at tutorialspoint wish you best luck to have good interviewer and all the very best for your future endeavor cheers :-processing math