# Lesson 1

Standard Units of Measure

### Lesson Purpose

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.

### Lesson Narrative

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.

• Representation

### Learning Goals

Teacher Facing

• Measure by iterating same-size length units.

### Student Facing

• Let’s measure length.

### Required Materials

Materials to Gather

### Required Preparation

Activity 1:

• Create a 40-cm length of string or ribbon for each group of 23.
• Create five 10-cm length straws for half of the groups of 23.
• Create ten 5-cm length straws for half of the groups of 23.

Activity 2:

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

Building On

Building Towards

### Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 20 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

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?

### Suggested Centers

• Target Numbers (1–5), Stage 5: Subtract Two-digit Numbers (Addressing)
• Five in a Row: Addition and Subtraction (1–2), Stage 6: Add within 100 with Composing (Supporting)