Lesson 3

The goal of this lesson is for students to understand that we can generally approach $p+x=q$ by subtracting the same thing from each side and that we can generally approach $px=q$ by dividing each side by the same thing. This is accomplished by considering what can be done to a hanger to keep it balanced.

Students are solving equations in this lesson in a different way than they did in the previous lessons. They are reasoning about things one could “do” to hangers while keeping them balanced alongside an equation that represents a hanger, so they are thinking about “doing” things to each side of an equation, rather than simply thinking “what value would make this equation true.”