Lesson 21

The purpose of this lesson is for students to compare two-digit numbers that are represented in different ways.

In previous lessons, students compared numbers and used the symbols <, >, and =. Students also represented two-digit numbers with different amounts of tens and ones.

In this lesson, students compare two-digit numbers that are represented in different ways. Students use what they have learned about tens and the structure of two-digit numbers to compose or decompose tens to make sense of representations and compare (MP7). In the first activity, students consider two collections that are represented in different ways and determine which has more. In the second activity, students compare numbers shown as different base-ten representations and write comparison statements using the symbols <, >, and =.

Think about a recent time from class when your students were confused. What did you do to support them in reasoning about their confusion together as a community of learners?