The mathematical purpose of this lesson is to remind students of the number line as a tool for representing inequalities and to support strategies for reasoning about inequalities by testing points. This lesson builds on the work students did in grades 6 and 7 when they began representing solutions to inequalities on the number line. The work in this lesson will prepare students for the associated Algebra 1 lesson in which they create solutions to inequalities and check the solutions by using substitution.

Students have an opportunity to reason abstractly and quantitatively (MP2) as they test specific values in inequalities. They look for and express regularity in repeated reasoning (MP8) as they generalize to represent all solutions on the number line.