The method fits the question. Anything where time changes the answer gets simulated step by step, because a shortcut formula would miss what actually happens. Everything else is direct arithmetic done exactly. No tool is forced into a shape that does not suit it.
Every fixed figure traces to a primary source. Roasting times come from USDA guidance. Wind chill and heat index use the published NWS and NOAA formulas. Exchange rates come from the European Central Bank, dated. Cost-of-living figures come from national statistics offices. Where no authoritative source exists, we say so and leave the field for you.
Assumptions are inputs, not hidden constants. Wherever an answer depends on something estimated - an interest rate, an oven, a grading scale, a city - that choice is yours to change, and the result moves with it.
Each one is covered by automated tests. Worked examples that run on every build, so a change to one tool cannot quietly break another.