# Lesson 2

Características de una recta numérica

### Lesson Purpose

The purpose of this lesson is for students to identify and describe the defining features of a number line.

### Lesson Narrative

In a previous lesson, students were introduced to number lines and represented the location of numbers with labeled tick marks and points within 20.

In the first activity, students each get a number and work together to decide how to place their numbers on a class number line, thinking about the importance of equal spacing and sequencing numbers from left to right. In the second activity, students analyze different student-created number lines and suggest revisions that should be made to make each number line a more accurate representation. Throughout the lesson, students deepen their understanding of the structure of the number line by attending to precision and thinking about the ways they can describe how to correct or improve a number line to others (MP3, MP6).

• Action and Expression

Activity 1: La recta numérica de la clase

### Learning Goals

Teacher Facing

• Describe the structure of a number line.

### Student Facing

• Exploremos las características de una recta numérica.

### Required Materials

Materials to Gather

Materials to Copy

• Class Number Line Cards (0–30)

### Required Preparation

Activity 1:

• Hang yarn across the classroom (yarn should be hung taut to resemble a line) for students to hang their number cards on.
• Create a set of number cards from the blackline master.
• Fold the number cards so they can be hung on the line.

### Lesson Timeline

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

### Teacher Reflection Questions

Reflect on who participated in class today. What assumptions are you making about those who did not participate? How can you leverage each of your students’ ideas to support them in being seen and heard in tomorrow’s class?

### Suggested Centers

• Five in a Row: Addition and Subtraction (1–2), Stage 6: Add within 100 with Composing (Supporting)
• How Close? (1–5), Stage 3: Add to 100 (Supporting)