This lesson enables students to experience the idea of a distance function before they learn about such functions more formally. The function comes up naturally in the context of computing absolute errors. This lesson is built around the idea of guessing a target number and examining how far the guesses are from it.

Advanced preparation is required for this lesson. See Required Preparation.

Students guess the number of objects in a collection and calculate how far off each guess is from the actual value. The distance between the guess and the actual value is called the absolute guessing error. Then they analyze the plot of the absolute guessing error to generalize to similar cases with a different target value.

Technology isn't required for this lesson, but consider making it available, as there are opportunities for students to choose to use appropriate technology to solve problems (MP5). It also helps the class process the collected data more efficiently.

The blackline master for the Warm-up activity, which includes two tables and two blank coordinate planes, will be used throughout the lesson.