# Lesson 1

Measure in Halves of an Inch

### Lesson Purpose

The purpose of this lesson is for students to measure lengths that are fractions of an inch and relate these measurements to fractions on a number line.

### Lesson Narrative

In grade 2, students learned how to measure lengths to the nearest inch. They also learned how to represent fractions on the number line in the previous unit.

In this lesson, students start by measuring the length of objects using an inch ruler. As students find objects whose length is not a whole number of inches, they consider how to partition the inches to get a more precise measurement. Students then partition a ruler to show halves of an inch and use the ruler to measure lengths to the nearest half of an inch. The lesson synthesis introduces students to mixed numbers as numbers that combine whole numbers and fractions less than 1.

Students use the rulers they make in this lesson again in future lessons.

• Engagement
• MLR2

### Learning Goals

Teacher Facing

• Measure lengths using a ruler marked with halves of an inch.

### Student Facing

• Let’s measure the length of objects around the room.

### Required Materials

Materials to Gather

Materials to Copy

• Measure Around the Room

### Required Preparation

Activity 1:

• Make copies and cut out the rulers from the blackline master (5 rulers per page).

Activity 2:

• Each student needs a ruler from the previous activity.

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 the last unit, students learned how to represent fractions on diagrams and number lines. In what ways did you see students applying that experience here?

### Suggested Centers

• Estimate and Measure (1–4), Stage 2: Centimeters and Inches (Supporting)
• Target Measurements (2–5), Stage 1: Inches and Centimeters (Supporting)

### Print Formatted Materials

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