Open the lid.

01 / Data rules

A catalogue match that knows when to stop

A product code, quantity and unit go in. Exact matches produce an integer-cent subtotal; missing codes and unit mismatches go to review instead of becoming invented prices.

The result: three units at $12.50 produce a $37.50 matched subtotal. Three other rows need review, so the overall result is not a final quote.

What it shows: explicit matching rules, exception handling and runnable checks for bad quantities, duplicate codes and currency limits.

Boundary: JSON input and JavaScript source; no PDF extraction, spreadsheet import or live purchasing integration.

02 / Web checks

Five small HTML problems, made visible

A source-review demonstration identifies a missing page title, missing viewport, duplicate IDs, an image without alt text and a placeholder link. The sample report pairs each finding with a correction.

What it shows: concrete findings with practical next steps.

Boundary: narrow source heuristics. Passing these checks does not establish accessibility compliance or prove that a page works in every browser.

03 / Study notebook · 11 September 2026 · v1

Keep the excluded values.

Algebra practice turned into a useful reminder about software: simplifying a rule can erase information about where it applies. I wrote up one small example and a limit on that analogy.

What I did: saved original attempts, checked published practice solutions afterward, and reviewed a separate assignment with algebraic reasoning and numerical checks. The note is my own reflection, not a course handout.

Boundary: self-study and self-verification, not instructor grading, a completed college course, or a tested general theorem about software.