Guides
Longer explanations of the ideas behind the calculators — useful when you want to understand the method, not just get an answer.
All guides
- How to Calculate PercentagesEvery everyday percentage problem, explained with one idea and worked examples.
- How to Convert UnitsA reliable method for any unit conversion, including squared and cubed units.
- Rounding & Significant FiguresDecimal places, significant figures, rounding modes and floating-point surprises.
- How Date Calculations WorkLeap years, month-end rules, inclusive counting, ISO weeks and time zones.
- Mean, Median & Mode ExplainedWhat each average tells you, how to find it, and which one to use.
- Metric vs ImperialHow the two systems are built, where each is used, and quick mental conversions.
- Order of OperationsPEMDAS and BODMAS, the left-to-right rule, and the classic traps.