Lesson 10

The purpose of this lesson is for students to round and order decimals to the nearest one, tenth, and hundredth.

In this lesson, students round numbers to different place values in context. In addition to rounding numbers, students determine the possible value of a number, given the numbers it rounds to. When students interpret the speeds and times as they might be rounded to different places and how this would influence their order they reason abstractly and quantitatively (MP2).

While not required, number lines can be helpful throughout this lesson to visualize which whole number, tenth, or hundredth is closest to a given quantity. Locating all the numbers on the same number line accurately will be challenging, but students can locate them individually to help round or they can estimate the locations in order to compare decimals.

Think about times when students were able to make connections to and build on the ideas of their peers during discussions today. What norms or routines allowed students to engage with other students’ ideas?