A good opening to a standard lesson is characterized by actions and statements made by the teacher that are designed to relate the experiences of the students to the objectives of the lesson. Each day of your teaching career you will start a 'new' spelling lesson, or a 'new' math lesson.
New lessons are as wide as the spectrum of the curriculum.
It is new because the pupils haven't experienced that particular lesson yet. Your task, as the teacher, will be to start the lesson in such a way that your pupils approach the lesson's task with a positive mind 'set'. Research reveals that pupils remember best those things they intend to remember. In other words, pupils need a positive set or outlook toward a new task if they are to learn it well. Ausubel refers to this as 'set induction'.