In an earlier lesson, students learned the importance of using a standard unit to ensure that they can communicate clearly about their measurements. They learned that a single base-ten block is a centimeter cube because each edge of the cube is 1 centimeter long.

The purpose of this lesson is for students to measure in centimeters and consider more efficient ways to measure. Students use tools (base-ten blocks) that have lengths of 1 centimeter and 10 centimeters to measure the length of objects. In the Warm-Up and in the first activity, students begin a transition from describing their measurements of length based on the number of objects they use to describing the number of standard length units (centimeters) the objects represent. In the second activity, students choose to measure with centimeter cubes or 10-centimeter tools (base-ten block “tens”) and explain their choices (MP5).

Give students access to base-ten blocks during the Cool-Down.

What evidence have students given that shows they understand that a centimeter is a length unit? What language do they use to describe how they measure a length in centimeters?