# Lesson 21

Día 3 de centros

### Lesson Purpose

The purpose of this lesson is for students to practice adding  within 20.

### Lesson Narrative

In Activity 1, students learn stage 1 of the center, How Close? In Activity 2, students learn stage stage 3 of the center, Five in a Row. In both activities, students have opportunities to apply methods and concepts from the section such as counting on, making a ten, adjusting addends (using known facts), and using the commutative and associative properties.

• Action and Expression
• MLR8

### Learning Goals

Teacher Facing

• Students add two and three numbers within 20.
• Students write equations with three addends.

### Student Facing

• Juguemos juegos en los que sumamos y restamos.

### Required Materials

Materials to Gather

Materials to Copy

• How Close? Stage 1 Recording Sheet, Spanish
• Five in a Row Addition and Subtraction Stage 3 Gameboard, Spanish

### Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 20 min Lesson Synthesis 10 min

### Teacher Reflection Questions

What methods are students using to add three numbers? What questions have you asked to encourage them to make a ten?