# Lesson 4: Mathematics, The M Word

>A tiny bit of mathematics. Really.

> "When I imagine a triangle, even though such a figure may exist nowhere in the world except in my thought, indeed may never have existed, there is nonetheless a certain nature or form, or particular essence, of this figure that is immutable and eternal, which I did not invent, and which in no way depends on my mind."<br>
René Descartes (1596-1650), *Meditations on First Philosophy* (1641)

This lesson is constructed like most. We'll start with some goals, move smoothly into a short biography of an important character in the story, and then to the content. This one's a little different. I'm going to use some mathematics in QS&BB and it's important for you to understand why and gain confidence that like Goldilocks, we'll do just enough.<br><br>
This lesson is a little more review and reference-like than the rest. Some of you may have seen much of the content of this lesson. I'd point you to the *Descartes,* *M Word*, and  *Functions, the QS&BB Way* sections.

```{note} &nbsp; Goals of this lesson
Understand, Appreciate, Familiarity
```

I'd like you to Understand:<br>
- Simple one-variable algebra.
- Exponential notation.
- Scientific notation.
- Unit conversion.
- Graphical vector addition and subtraction.

I'd like you to Appreciate:<br>
- The approximation of complicated functions in an expansion.

I'd like you to become Familiar With:<br>
- Aspects of Descartes’ life.
- The importance of Descartes’ merging of algebra and geometry.