Lesson 20

Formemos números de dos dígitos de diferentes maneras

Lesson Purpose

The purpose of this lesson is for students to represent two-digit numbers in different ways and identify two-digit numbers represented with different amounts of tens and ones.

Lesson Narrative

In the previous lesson, students explored representing a two-digit number with tens and ones. The purpose of this lesson is for students to represent two-digit numbers with tens and ones in different ways and identify two-digit numbers when they are represented with different combinations of tens and ones. As students reason about different ways to compose or decompose tens, they look for and make use of the base-ten structure of two-digit numbers (MP7). In the first activity, students represent 94 with tens and ones in as many ways as they can and discuss how they know that they have found all of the ways. In the second activity, students determine how many connecting cubes are in each mystery bag and how they are grouped, given clues based the number of tens and ones in each bag.

  • Action and Expression
  • MLR8

Activity 2: Bolsas misteriosas

Learning Goals

Teacher Facing

  • Identify two-digit numbers represented in different ways.
  • Represent two-digit numbers in different ways using tens and ones.

Student Facing

  • Formemos números de dos dígitos de diferentes maneras.

Required Materials

Required Preparation

CCSS Standards


Building Towards

Lesson Timeline

Warm-up 10 min
Activity 1 20 min
Activity 2 15 min
Lesson Synthesis 10 min
Cool-down 5 min

Teacher Reflection Questions

What question do you wish you had asked today? When and why should you have asked it?

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