In this lesson, students write descriptions for situations that could be represented by given graphs, then draw graphs for given descriptions. The mathematical focus of the lesson is recognizing what is happening in a situation when functions increase or decrease, so that students can refer to these situations in future lessons. In the associated Algebra 1 lesson, students compare two functions using the average rate of change and function values. Students are supported by examining simpler functions to recognize when they are increasing and decreasing, as well as by looking at different graphs based on the same descriptions, to compare the results and recognize some aspects that must be true.

Students draw graphs that represent populations of cities, towns, and villages that have given properties (MP2). Attention to precision (MP6) is also essential when recognizing features of those graphs that must be present and features that could be open to interpretation.