Is it permissible to offer free mixed remedial classes given the existing gender mixing in education, and what is the advice that must be followed when a boy sits next to a girl in the classroom?

Mixing in educational institutions is forbidden due to the great corruptions it entails. There must be segregation between genders at different educational stages, and men should teach boys while women teach girls. A man working in a mixed school is permissible if he is safe from temptation and adheres to the Islamic guidelines, such as lowering his gaze and avoiding private seclusion with non-mahram (definition) women. However, if he fears temptation, or is exposed to private seclusion, touching, or forbidden looking, then it is not permissible. In supplementary classes, the teacher can separate the genders by time or place so that differentiation occurs and the prohibition is removed.