# Lesson 3

Sumar y restar con decenas

### Lesson Purpose

The purpose of this lesson is for students to add and subtract 10 from multiples of 10.

### Lesson Narrative

In this lesson, students build on their understanding of tens as they add 10 to and subtract 10 from multiples of 10. Students learn that they can think of adding or subtracting 10 as adding or subtracting a ten from a number of other tens. In the first activity, students use towers of 10 to physically add or subtract a ten from a multiple of 10. In the second activity, students learn a new stage of the Five in a Row center, where they choose a card with a multiple of 10 and decide whether to add or subtract 10 in order to cover five spaces in a row on their gameboard. They may choose to continue to use towers of 10 if helpful.

• Action and Expression
• MLR8

### Learning Goals

Teacher Facing

• Add and subtract 10 from multiples of 10.

### Student Facing

• Sumemos y restemos 10.

### Required Materials

Materials to Gather

Materials to Copy

• Five in a Row Addition and Subtraction Stage 4 Gameboard, Spanish
• Number Cards, Multiples of 10 (0-90)

### Required Preparation

Activity 2:

• Create a set of cards from the blackline master for each group of 2.

Activity 3:

• Gather materials from previous centers:
• Five in a Row, Stages 1–4
• How Close, Stages 1 and 2
• Number Puzzles, Stages 1 and 2

Building Towards

### Lesson Timeline

 Warm-up 10 min Activity 1 10 min Activity 2 15 min Activity 3 15 min Lesson Synthesis 10 min Cool-down 0 min

### Teacher Reflection Questions

Reflect on times you observed students listening to one another’s ideas today in class. What norms would help each student better attend to their classmates’ ideas in future lessons?