If you master the chapter Solving Linear Equations , you will find the solution of many problems in high-school lessons on slopes, rates of change and proportionality constants in mathematics, commerce, chemistry and physics, simpler to do. This chapter gives more reinforcement for your command of the algebraic way of writing and reasoning. The two chapters Painless Theorem Proving and The Pythagorean Theorem provide light digressions. The first shows how an arithmetic calculation may prove a statement. The second gives the Chinese square dissection proof of the Pythagorean Theorem.
Some algebra appears.
The Geometry directory includes another proof. The aim here is clarity, not confusion. But the chapter is long. It is for gifted students and others with the patience to read it. Chapters Functions and Sets and , Degrees and Radians provide further digressions.