Lesson 7

The goal of this lesson is for students to understand that we can generally approach equations of the form \(px+q=r\) by subtracting \(q\) from each side and dividing each side by \(p\) (or multiplying by \(\frac{1}{p}\)). Students only work with examples where \(p\), \(q\), and \(r\) are specific numbers, not represented by letters. 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” or reasoning with situations or diagrams.