Lesson 12

The purpose of this lesson is for students to compare two multi-digit whole numbers within 1,000,000 by reasoning about place value and to explain how they make comparisons.

Previously, students learned to build, read, name, and write multi-digit whole numbers up to six digits. They also developed an understanding of the relationship between a digit in one place and the same digit in the place immediately to its right. Through that work, students built their intuition for the relative size of numbers.

In this lesson, students use their understanding of place value to compare numbers and articulate how they reason about the size of the numbers. In doing so, they reinforce their understanding of place value and the base-ten number system (MP7). In communicating their thinking, they also practice attending to precision (MP6).

• Each group of 2 needs a set of cards from the previous activity.

Today’s work on comparison relies on students’ understanding of place value and numbers in base ten. How readily did students connect today’s activities to their prior knowledge? What connections could have been made but were missed?