1. Choose a tool from the list. On a phone, use the menu at the top.
2. Select an example or change the values, then press “Calculate.” Enter also works in single-line fields.
3. Read the answer and diagram, then open “Show the steps” to follow the method.

“Exact” means integer or rational arithmetic applied to the entered values. “Approximate” means a numerical estimate and may include method error or decimal rounding. When an interval is shown, use its width to judge precision.

Wasan can be understood through modern mathematics. This laboratory preserves its characteristic questions and computational viewpoints while making any modern reconstruction explicit.

All numerical calculations run in this browser.