# Lesson 17

Día 3 de centros (optional)

### Lesson Purpose

The purpose of this lesson is for students to practice adding and subtracting within 1,000.

### Lesson Narrative

This lesson is optional because it is an opportunity for extra practice that not all classes may need. In Activity 1, students learn stage 6 of the Target Numbers center. In this new stage, called Add Hundreds, Tens, or Ones, students add hundreds, tens, and ones to get as close to 1,000 as possible. In Activity 2, students learn Stage 7 of the Target Numbers center, called Subtract Hundreds, Tens, or Ones. Then, they choose to continue working on Target Numbers, or choose between two previously introduced centers focused on addition and subtraction within 1,000.

### Learning Goals

Teacher Facing

• Subtract within 1,000.

### Student Facing

• Sumemos y restemos números de 3 dígitos.

### Required Materials

Materials to Gather

Materials to Copy

• Target Numbers Stage 6 Recording Sheet, Spanish

### Required Preparation

Activity 1:

Each group of 2 needs 3 number cubes.

Activity 2:

• Each group of 2 students needs 3 number cubes.
• Gather materials from:
• Target Numbers, Stage 6
• Five in a Row, Stages 7 and 8
• How Close, Stage 4

### Lesson Timeline

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

### Teacher Reflection Questions

Reflect on whose thinking was heard today. Reflect on whose thinking was not heard but could have enriched the conversations. What prompts or structures might better enable the latter to share their voices and reasoning?