In this lesson, students use place value to compare numbers. In kindergarten, students used the terms “more than,” “less than,” and “fewer than” to compare groups of objects and numbers. In this lesson, students compare numbers using the language “greater than” and “less than.” In the first activity, students represent two-digit numbers and then compare them. In the second activity, students make sense of and critique the way others use the digits in two-digit numbers to compare values. In the Lesson Synthesis, students are asked to think about why we only need to compare the tens when comparing two-digit numbers, if the digit in the tens place is different in each number. It is important for students to understand that comparing the digits in the tens place is sufficient because we know there can’t be more than 9 ones, because the value in the ones place will always be less than 1 ten.

Today students used the value of the digits in the tens and ones place to compare numbers. Why is it important to encourage students to be precise when explaining how they use the digits in the numbers to compare?