Lesson 10
El valor posicional y la recta numérica
Lesson Purpose
The purpose of this lesson is for students to compare representations of addition and subtraction methods represented on the number line.
Lesson Narrative
In previous lessons, students matched addition and subtraction equations and their representations on a number line. They found the value of differences within 100 and represented their thinking on a number line.
In this lesson, students add and subtract within 100 and represent computation methods on a number line. They compare representations of methods based on place value and make connections across representations (MP2). The expressions in each activity include numbers that elicit methods based on counting on or counting back by place.
- Representation
- MLR8
Learning Goals
Teacher Facing
- On a number line, represent place value methods for solving addition and subtraction equations that do not require decomposing a ten.
Student Facing
- Comparemos métodos usando la recta numérica.
Required Materials
Materials to Gather
Required Preparation
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
Why is it important for students to be able to represent their thinking and strategies using varied representations? How can you support students to feel comfortable using other representations?
Suggested Centers
- Number Puzzles: Addition and Subtraction (1–4), Stage 4: Within 100 with Composing (Addressing)
- Number Line Scoot (2–3), Stage 1: Twos, Fives, and Tens (Addressing)