Lesson 1

The purpose of this lesson is for students to measure by iterating same-size length units and identify the need for standard units of measurement.

In grade 1, students learned how to measure length by laying multiple copies of a shorter object end to end without gaps or overlaps. In this lesson, students use these measuring skills to measure the length of objects by iterating with straws and centimeter cubes. In the first activity, students use different length units when measuring the same objects and see that this leads to different measurements. In the second activity, all students use the same length unit (centimeter cubes) and see they all find the same measurement. In the lesson synthesis, students are introduced to the centimeter as the length of a centimeter cube. Students will use the centimeter as a length unit in future lessons.

Give students access to centimeter cubes during the cool-down.

• Create a 40-cm length of string or ribbon for each group of 2–3.
• Create five 10-cm length straws for half of the groups of 2–3.
• Create ten 5-cm length straws for half of the groups of 2–3.

• Gather a connecting cube to display in the activity synthesis. Students will not need connecting cubes for this activity.

In grade 1, students measured by iterating same-size length units. How did students demonstrate their understanding and skill with measurement in this lesson? What can you do in future lessons to build on these strengths?