We write the answer first, then show the formula, a worked example, the rule citation and its verification status. The repository’s reference/RULES.md is the calculation source of truth. Competitor pages and search research are used for wording and navigation, never to alter rules.
Last rule checks: labour 12 November 2026; tax 13 November 2026. The tax gazette has not been independently read for this build. Legal sign-off and the owner’s Bangla copy review remain pending. We do not name an expert reviewer or imply one has approved the content. Corrections must update the rule reference and pass the fixed calculation tests before release.