Naegele's rule using your cycle length. Roughly 4% of due dates are off by more than a week — this is an estimate, not a medical prediction.
Sort a graph's edges by weight and take each one that does not close a cycle, with union-find deciding. Reports the total weight and how many components survive.
Order tasks so every dependency comes first, using Kahn's algorithm, and detect a cycle by the tasks that can never become ready.
Decimal to Roman and back, validated strictly: a numeral is only accepted when re-encoding its value reproduces the input exactly, with a count of the symbols used.
Principal, rate, years and a monthly deposit drawn as a real growth curve, with the year-by-year split of interest against principal.
Type a size and a label, then download a real PNG, a real SVG or a copyable data URI.
Infer a draft-07 schema from an example value, edit it, then validate a document and read every error path.
A real SM-2 deck: grade each card Again, Hard, Good or Easy and get true intervals, real due dates and a 21-day forecast.
Write multiple-choice questions, mark the key, then run the quiz shuffled and score it with a review list of every miss.
