Overview:  The teacher launches the lesson by telling students they will work on a problem where they can learn a mathematical idea through the practice of paper folding.  The teacher reminds students that paper folding is likely an activity that they have done since they were children.  Students offer different experiences that they have of folding paper.  Students’ experiences include making paper dolls, snowflakes, and paper airplanes.  After generating some of students’ memories of paper folding, the teacher points out to students that paper folding is not only an activity for young people, but actually there are sophisticated mathematical ideas related to paper folding.

Prior knowledge:  With the examples of paper folding, the teacher connects to students’ experiences with a mathematical practice.  Paper folding is a mathematical activity, specifically in that it can be used as a way of making geometric constructions including a perpendicular bisector (NGAC, 2010).  Also, students have practiced paper folding in many different contexts outside of school mathematics.  The teacher attempts to bridge students’ prior experiences with their current task.

Other points of interest:  With the launch, the teacher suggests to students that the mathematical practice of paper folding has value for solving the problem.  The teacher may suspect that, because paper folding is an activity that many students do when they are young, the students in the class will not think of paper folding as an appropriate way to solve a problem in geometry.  Students’ memories of paper folding activities suggest that they may not see these activities as inherently mathematical.  Because of this, the teacher needs to not only connect with students’ prior knowledge of the practice of paper folding but also convince students that this knowledge is valuable for solving the problem.