In this lesson, students use average rate of change to connect their understanding of slopes from linear graphs with their understanding of increasing, constant, and decreasing sections of a nonlinear graph.

Students learn that average rate of change can be used to measure how fast a function changes over a given interval. This can be done when we know the input-output pairs that mark the interval of interest or by estimating them from a graph.

Attention to units is important in computing or estimating average rates of change because units give meaning to how much the output quantity changes relative to the input. In thinking carefully about appropriate units to use, students practice attending to precision (MP6).

Students also engage in aspects of mathematical modeling (MP4) when they use a data set or a graph to compute average rates of change and then use it to analyze a situation or make predictions.