11 Volume 2 — Patterns and algebra
The central move of this volume is naming the gap.
You already know how numbers behave. This volume is about what happens when one of the numbers is missing — and about the notation that lets you work with that absence as if it were a thing you could hold.
By the end of this volume you will be able to write a relationship down symbolically, solve for unknowns, recognise when a relationship is linear versus something else, and read a graph as a statement about how two quantities relate.
These are not abstract skills. They are the toolkit that every quantitative field — engineering, science, finance, computing, geography — uses before it reaches for anything more sophisticated.
11.1 Chapters
| Chapter | Title | Core move |
|---|---|---|
| 1 | Linear equations | Isolating the unknown |
| 2 | Inequalities | When the answer is a range |
| 3 | Patterns and sequences | When the relationship repeats |
| 4 | Graphing relations | When the relationship has a shape |