Is it unlawful for a teacher to help students answer exam questions that were not mentioned in the lesson plan, and are the students sinful for writing these answers?

The fundamental principle is that a teacher must complete the academic curriculum, both in teaching and examination, to reveal the students' true level. Therefore, it is not permissible for him to specify the locations of exam questions or to inform students of the answers, whether explicitly or implicitly. The teacher is entrusted not to indicate the locations of the questions. The important thing is for the student to succeed through merit, not for us to simply increase the number of certificate holders. If the teacher informs students of the answer to a question, it appears that it is not forbidden for the student to write it down, provided the student did not seek for the teacher to mention the answer. This is a provision that came without effort.