In this lesson, students use graphs to learn about the domain and range of functions, while continuing to think about what values are reasonable in the given situations.

Students learn to look for graphical features that help them identify restrictions to the input or output. For example, they recognize that maximums and minimums, intercepts, and gaps on the graph can be quite informative. They also see that discrete points or breaks in a graph suggest that not all values can be in the domain or range, and that a graph may only partially represent a function. The work here offers opportunities to look for and make use of structure (MP7).

When describing domain and range, students also practice attending to precision by minding relevant details in the graphs and descriptions of functions (MP6).