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Methods and reliability
An answer is useful only when its assumptions, calculation method and limits are visible.
Checks and presentation
Calculations are checked against examples and boundary cases. Non-finite results are rejected. Display rounding is separate from calculation; very small valid values can use scientific notation. All interface numbers use 0123456789 with local separators; user text and files are not rewritten.
Calendars and sensitive estimates
Calendar pages declare each algorithm, supported range and era. Civil Hijri dates may differ from official calendars or local observation. Inheritance uses a bounded Saudi 2022 method; zakat uses the stated individual method. Unsupported cases are refused. General school age uses your dates, not an unverified current admission rule.
Sources and correction
Relevant tool pages link their sources and worked examples. Editorial source-review dates are not specialist certification. Changeable rules are scheduled for review every 90 days and stable methods annually; the owner sees overdue reviews. Report a reproducible discrepancy through Contact without sending sensitive data.
Updated September 8, 2026