# AMC 8 — skill taxonomy

The canonical topic list for tagging AMC 8 problems (competition math, 25 MCQ, no calculator). Same role as
SAT's skill-taxonomy: every problem gets one of these ids so banks + weak-spots aggregate cleanly.

**⭐ = one of Daisy's 9 focus areas** (her review topics from the prior session; see
`study/students/daisy/amc8.md`). Reconstructed from the topic tags in `Set 3` (the fuller session ran on
claude.ai — Sets 1–2 + the original analysis not yet on disk).

## Number Theory
| id | topic | ⭐ |
|---|---|---|
| `nt-units-digit` | Units (ones) digit / cyclicity | ⭐ |
| `nt-divisor-counting` | Divisor counting (from prime factorization) | ⭐ |
| `nt-divisibility-counting` | Divisibility counting (inclusion–exclusion, ⌊n/k⌋) | ⭐ |

## Counting & Probability
| id | topic | ⭐ |
|---|---|---|
| `cp-dice-complementary` | Dice & complementary counting | ⭐ |
| `cp-lattice-paths` | Lattice paths (grid, right/up steps) | ⭐ |
| `cp-arrangements` | Counting arrangements (permutations) | |
| `cp-combinations` | Combinations / handshakes (n choose 2) | |

## Geometry
| id | topic | ⭐ |
|---|---|---|
| `geo-shaded-circles` | Shaded area with circles | ⭐ |
| `geo-incenter-angle` | Incenter angle (angle-bisector, 90+A/2) | ⭐ |
| `geo-coordinate-area` | Coordinate area / shoelace | ⭐ |
| `geo-similar-triangles` | Similar triangles | |
| `geo-pythagorean` | Pythagorean theorem / triples | |
| `geo-clock-angle` | Clock angle (hour/minute hands) | |
| `geo-painted-cube` | Painted cube (surface/faces) | |

## Algebra, Rates & Sequences
| id | topic | ⭐ |
|---|---|---|
| `alg-combined-rates` | Combined / work rates | ⭐ |
| `alg-average-speed` | Average speed (harmonic mean) | |
| `alg-arithmetic-series` | Arithmetic series / sequences | |

*The 9 ⭐ = Daisy's focus areas. The 8 non-⭐ = the "new types" introduced in Set 3. Add rows as more sets /
topics come in. Don't rename an id once problems are tagged with it.*