This thing is very profitable. You don't need a substitute teacher, just find some part-time students to be teachers and correct your homework. The operating cost is low, a few exercise books don't need much money, and students charge low fees, which is in line with parents' expectations. But money is collected month by month. The teacher who counsels and communicates with parents must have been fooled. Smart parents can't see through this. Otherwise, no matter how little money you collect, he will definitely not come again next month. Parents will spread the news and the business will be over. Remember.