# Lesson 8

Varias representaciones de decenas y unidades

### Lesson Purpose

The purpose of this lesson is for students to interpret base-ten representations of two-digit numbers.

### Lesson Narrative

In previous lessons, students learned that the digit on the left of a two-digit number tells the number of tens and the digit on the right tells the number of ones.

In this lesson, students interpret three different base-ten representations: base-ten diagrams, _____ tens _____ ones, and addition expressions that represent the value of each digit. This is the first time students see expressions representing two-digit numbers other than 10 + n expressions representing teen numbers. Students match representations that show the same value.

At this time, students are not expected to write two-digit numbers, but continue to make sense of how to read and say them based on their base-ten structure. The teacher should record two-digit numbers when students say them.

• Engagement
• MLR7

Activity 1: Comparemos representaciones de una colección

### Learning Goals

Teacher Facing

• Interpret different base-ten representations of two-digit numbers (drawings, words, and addition expressions).

### Student Facing

• Pensemos cómo se pueden mostrar los números de dos dígitos.

### Required Materials

Materials to Gather

Materials to Copy

• Representations of Tens and Ones, Spanish
• Grab and Count Stage 2 Recording Sheet, Spanish

### Required Preparation

Activity 2:

• Create a set of cards from the blackline master for each group of 2–4.

### 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

What was the best question you asked students today? Why would you consider it the best one based on what students said or did?