The Montessori presentation of lessons revolves around the three-period lesson.
1. Show me.
In the first presentation of material, the teacher demonstrates to the child the proper process of using a material. Her vocabulary is limited to naming the associated words with the material. For example, when teaching the geometric solids, she may put out cube, rectangular prism, and cylinder. The process involves getting out the rug, bringing the basket to the work area, and carefully handling each solid with two careful hands. She names each solid as it is presented and will often repeat the names as she points to each one on the rug.
2. Ask me.
In the second period, the child is asked to point to each item as the teacher names it. She will say, "Show me the cylinder. Show me the rectangular prism. Show me the cube." If the child makes a mistake, the lesson is over and can be resumed on another day.
3. Tell me.
In the third period, the child has to provide the given vocabulary. The teacher will point to each solid and ask, "What is this?" The child will answer accordingly. Again, should he make a mistake, the lesson is over and is resumed on another day.
Children often stay in the second period for quite some time. They practice the materials and vocabulary again and again. When they are able to correctly name all of the items, mastery is complete and the child is ready to move on to the next lesson in the sequence.