In Topic B, students learn that intervals do not have to be whole numbers, but can also have fractional values that facilitate recording measurement data with greater precision. In Lesson 5, they generate a six-inch ruler marked in whole-inch, half-inch, and quarter-inch increments, using the Module 5 concept of partitioning a whole into parts. This creates a conceptual link between measurement and recent learning about fractions. Students then use the rulers to measure the lengths of pre-cut straws and record their findings to generate measurement data (**3.MD.4**).

Lesson 6 reintroduces line plots as a tool for displaying measurement data. Although familiar from Grade 2, line plots in Grade 3 have the added complexity of including fractions on the number line (**2.MD.9**,** 3.MD.4**). In this lesson, students interpret scales involving whole, half, and quarter units to analyze data. This experience lays the foundation for them to create their own line plots in Lessons 7 and 8. To draw line plots they learn to choose appropriate intervals within which to display a particular set of data. For example, to show measurements of classmates’ heights, students might notice that their data falls within the range of 45 to 55 inches, and construct a line plot with the corresponding interval.

Students end the module by applying learning from Lessons 1–8 to problem solving. They work with a mixture of scaled picture graphs, bar graphs, and line plots to problem solve using both categorical and measurement data (**3.MD.3**, **3.MD.4**).