A teacher uses his teaching time in activities and other things
Question

                What is the ruling on a teacher who uses the time that is supposed to be used for teaching students a specific subject in doing other things such as computers, activities, or any other matter?.
Praise be to Allah.
    Undoubtedly the basic job of a teacher is to teach the 
    classes allocated to him, but other things such as activities, supervising, 
    preparing lessons and so on should also not be neglected, because they have 
    a beneficial effect on the students and on making people like school. The 
    student may benefit from these activities more than the lesson itself. The 
    school administration should organize these things and distribute these 
    tasks in such a manner that it will not affect the teacher’s performance in 
    his class. 

    If the teacher has been assigned these things by the 
    administration then there is nothing wrong with his doing them. 

    But if he is doing them on his own initiative, then he is to 
    be appreciated for that, but he should strike a balance, and not cause the 
    students to miss out on their due of explanation and teaching that they 
    need, or ask for a reduction in the classes that he gives so that he will be 
    free for these activities. He has to combine the two interests. 

    If the activities that he does are not important, or someone 
    else is giving them sufficient attention, or he is giving them too much 
    attention and wasting time with them, at the expense of doing his job in the 
    classroom, then undoubtedly this is neglecting his duty and betraying the 
    trust. “And Allaah knows him who means mischief from him who means good” 
    [al-Baqarah 2:220]. He should fear Allaah and get his priorities 
    straight. 

    Explaining the importance of activities and the obligation of 
    cooperating in organizing them, Shaykh Ibn Jibreen (may Allaah preserve him) 
    said:  We should cooperate and help one another in important matters that 
    are needed in the school, such as preparing articles, researching issues, 
    taking part in school activities, writing announcements, messages and advice 
    to inspire the school and its members to advance, giving a strong impression 
    to visitors of the strength of its activities, advice and ideas. Undoubtedly 
    this cannot be achieved by one or two people, and the principal should not 
    neglect this aspect and sit alone in the office and limit himself to making 
    each teacher teach his subject in the classroom; rather he must do more than 
    that, and encourage more student activities, and motivate them to do 
    righteous deeds, and encourage the students, teachers and employees to 
    cooperate with one another, and make some effort and spend some time on 
    writing memos and the like which will attract attention and impress 
    visitors, and demonstrate their sincerity towards students and others. If 
    the principal of the school does not do that, then the teachers should offer 
    suggestions and show their willingness to cooperate with him in the 
    interests of all. If the principal asks them or some of them to do some 
    tasks, then they should hasten to fulfil that request. This is something 
    that is required of everyone, and it comes under the heading of cooperating 
    in righteousness and piety. If money is needed to sponsor these activities, 
    then it is the duty of the one who is able to hasten to do that. Similarly 
    if the principal asks one of them to buy something important in the 
    interests of the school, and he is one who knows how to buy it and it is not 
    a great hardship, then it is the duty of brotherhood and friendship to 
    respond to the request and not limit himself to giving lessons inside the 
    classroom. Although that is his basic duty, there are other activities that 
    may be connected to this activity. It is known that the teacher’s working 
    hours are like those of any other worker; he should be available for the 
    whole time, from beginning to end. So if he is employed full-time, he should 
    not disdain to work with others in the interests of all. End quote from 
    al-Ajwabah al-Fiqhiyyah ‘ala As’ilah al-Ta’leemiyyah wa’l-Tarwabiyyah, 
    p. 21 

    And Allaah knows best.