This lesson is optional because it is an opportunity for extra practice that not all classes may need. In the first activity, students learn Stage 2 of the Estimate and Measure center, which was first introduced in grade 1. Students estimate and measure the length of objects and find the difference between their estimate and the actual measurement. In the second activity, students learn a new center, Target Measurements. In this center, students practice estimating and measuring length in inches and centimeters.

As students worked in their centers today, whose ideas were heard, valued, and accepted? How can you use what you learned today about your students to inform how you will use centers in the future?