In this lesson, students compute the value of when given the value for in linear equations. In another activity, students interpret similar values in a given situation and think about values that do not make sense for the variables in that situation. In the associated Algebra 1 lesson, students are introduced to function notation and interpret points in situations. Students are supported by doing almost the same work in this lesson using equations with and so that they may focus on the new function notation in Algebra 1.

Students reason abstractly and quantitatively (MP2) when they interpret values in the given situations. When students reason about what is a reasonable value for a context, they are engaging in an aspect of mathematical modeling (MP4).