# Exact curriculum boundary

Source: [QCAA Specialist Mathematics General senior syllabus 2025 v1.4](https://www.qcaa.qld.edu.au/downloads/senior-qce/syllabuses/snr_maths_specialist_25_syll.pdf), March 2026. Unit 1 is **Combinatorics, proof, vectors and matrices** (printed p 15), a notional **55-hour** unit (printed p 4). Unit 1 Topic 1, **Combinatorics**, has **two subtopics**: Introduction to counting techniques (**4 hours**) and Permutations (ordered arrangements) and combinations (unordered selections) (**8 hours**), printed pp 16–17. Ten 25-minute periods = **250 minutes = 4 hours 10 minutes**. Our scripts use those 250 minutes as an opening sequence around the first subtopic; the 10-minute difference is timetable structure, not a claim that QCAA changed its allocation.

| Official subject matter, paraphrased | Where the opener teaches it | Evidence and boundary |
| --- | --- | --- |
| Inclusion–exclusion for union of two sets | Days 1–2, 5, 9 | A/B, fresh G; overlap is subtracted once |
| Inclusion–exclusion for union of three sets | Days 3, 8–10 | C, fresh H; pairwise overlaps include the triple, which is added back |
| Multiplication principle | Days 6–7, 9–10 | E/F, fresh I; sequential choices form a product |
| Addition principle | Days 4, 7, 9–10 | D/F, fresh G/I; branches must be mutually exclusive or adjusted for overlap |
| Recall, use, communicate, reasonableness, justification, problem solving (Unit objectives, printed pp 15–16) | All days | Count, represent, check and explain in an accessible mode |
| Permutations/combinations including restrictions and probability | **Future 8-hour subtopic, not taught here** | No factorial, nPr/nCr or ordered-arrangement claim in this starter |
| Topic 2 proof; later vectors/matrices | **Future Unit 1 topics, not taught here** | A reason for a count is required, but no claim of formal Topic 2 proof coverage |

There are no invented official lesson codes. The two [public formative checks](STUDENT-CHECKS.md) and their worked key are not secure school instruments or a QCAA unit judgment. The syllabus, printed pp 4–5 and 14, leaves course/Unit 1 assessment decisions to schools. Queensland is the explicit alignment; do not relabel it as an approved course for another state or country without that jurisdiction's own crosswalk.