Writing is a form of communication that requires complex thinking and the ability to articulate through the written word so someone else can understand the thinking. Writing gives students an opportunity to explain, clarify, and solidify their thinking so they can share it with others. When a teacher reads a student’s writing, she or he is given the opportunity to see into the child’s mind and see what kinds of reasoning are taking place. Through reading a student’s writing, the teacher can get to know the learner better, can clarify misunderstandings, and enrich mathematical thinking. When students share their writing with each another, it leads to discussions, which honor students thinking, allow them to clarify understandings, and allow them to become more effective mathematicians.