Lesson 6

Formemos una decena y démosle sentido a las ecuaciones

Lesson Purpose

The purpose of this lesson is for students to add one-digit and two-digit numbers, with composing a ten, using place value understanding and the properties of operations. Students also make sense of equations that represent addition methods.

Lesson Narrative

In this lesson, students add one-digit and two-digit numbers by composing a ten using place value reasoning and properties of operations. The associative and commutative property are highlighted in this lesson.

The first activity uses 10-frame diagrams to encourage students to determine how many ones can be added to a two-digit number to get to the next multiple of 10. Much like they did when looking to make a ten when adding within 20, students consider decomposing a one-digit number in such a way that they can combine one part with the two-digit number to make a multiple of 10 (\(68 + 6 = 68 + 2 + 4 = 74\)).

In the second activity, students compare different representations of this method, including those that use connecting cubes and base-ten drawings. These representations help students use their understanding of place value to see that when adding ones to ones, they can sometimes make a new unit of ten. This is a conceptual jump for students from understanding that they can count to a “10” (or the next ten) to understanding that they can create a new unit of ten from 10 ones (MP7).

  • Engagement
  • MLR7

Activity 2: Elena y Andre suman

Learning Goals

Teacher Facing

  • Add a one-digit and a two-digit number, with composing a ten, using place value understanding and the properties of operations.
  • Make sense of equations that represent addition methods.

Student Facing

  • Sumemos números de un dígito y de dos dígitos, y démosle sentido a ecuaciones.

Required Materials

Materials to Gather

Materials to Copy

  • Target Numbers Stage 1 Recording Sheet, Spanish

Required Preparation

CCSS Standards


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

How did the work of Activity 1 lay the foundation for students to be successful in the next activity? What do students need to be fluent with in order to use the method presented in Activity 2?

Print Formatted Materials

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Student Task Statements pdf docx
Lesson Cover Page pdf docx
Teacher Guide Log In
Teacher Presentation Materials pdf docx
Blackline Masters zip