Lesson 3

Measure in Halves and Fourths of an Inch

Lesson Purpose

The purpose of this lesson is for students to use what they know about fraction equivalence to measure with a ruler that is marked with halves and fourths of an inch.

Lesson Narrative

Previously, students learned to measure lengths using separate rulers that were marked with halves or fourths of an inch. Here, they use what they know about fraction equivalence to read measurements from a ruler marked with both halves and fourths of an inch. Then, students consider lengths that could be named in more than one way.

In future lessons, this ruler will be used to measure objects and represent measurements in a line plot.

• Engagement
• MLR8

Activity 1: Halves and Quarters

Learning Goals

Teacher Facing

• Measure lengths using a ruler marked with both halves and fourths of an inch.
• Use equivalent fractions to describe length measurements.

Student Facing

• Let’s measure lengths in halves of an inch and quarters of an inch.

Required Materials

Materials to Gather

Materials to Copy

• Notice and Wonder Rulers

Required Preparation

Warm-up:

• Each group of 2 needs the rulers from the previous lesson.
• Cut out a ruler from the blackline master for each student.

Activity 1:

• Each student needs a ruler marked with half inches and quarter inches from the warm-up.

Activity 2:

• Each student needs a ruler marked with half inches and quarter inches from the previous activity.

Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 25 min Lesson Synthesis 5 min Cool-down 5 min

Teacher Reflection Questions

Think about who volunteered to share their thinking with the class today. Are the same students always volunteering, while some students never offer to share? What can you do to help the class understand the value of hearing the ideas of every mathematician?

Suggested Centers

• Estimate and Measure (1–4), Stage 3: Quarter Inches (Addressing)
• Target Measurements (2–5), Stage 2: Quarter Inches (Addressing)
• Creating Line Plots (2–5), Stage 1: Inches and Centimeters (Supporting)