# Lesson 2

Cómo saber si ya contamos (optional)

### Lesson Purpose

The purpose of this lesson is for students to keep track of objects that have been counted in order to accurately count groups of up to 20 objects.

### Lesson Narrative

This lesson is optional because it is an opportunity for extra practice keeping track of and accurately counting groups of up to 20 objects. When counting larger groups of objects, it is more likely that students will skip some objects or recount objects more than once which highlights the need to organize and keep track while counting. The second activity provides opportunities to practice different ways of keeping track of objects in order to count accurately.

• Engagement
• MLR8

### Learning Goals

Teacher Facing

• Answer “how many” questions about groups of up to 20 objects.
• Keep track of objects that have been counted.

### Student Facing

• Descifremos cuántos objetos hay en nuestras colecciones.

### Required Preparation

Activity 1:

• Each student needs a collection of 11-20 objects.

Activity 2:

• Each student needs a collection of 11–20 objects.
• Students need the 10-frames and counting mats from the previous activity.

Activity 3:

• Gather materials from:
• Number Race, Stages 1 and 2
• Subtraction Towers, Stage 1
• 5-frames, Stages 1 and 2

Building Towards

### Lesson Timeline

 Warm-up 10 min Activity 1 10 min Activity 2 10 min Activity 3 25 min Lesson Synthesis 5 min Cool-down 0 min

### Teacher Reflection Questions

When do your students feel successful in math? How do you know?