Lesson 18

The mathematical purpose of this lesson is to review the meaning of inequality symbols, especially in contexts which involve positive and negative numbers. At the start of the lesson, students notice and wonder about statements involving inequality symbols, giving them a chance to activate prior knowledge of inequalities from grade 6, and giving you a chance to understand what meaning they make of the expression. 

Later in the lesson, students have a chance to reason abstractly and quantitatively (MP2) by interpreting inequalities in context and considering multiple representations of the same inequality. This will be useful in the associated Algebra 1 lesson when students write inequalities to represents the constraints in a situation.