Contact
Write to hello@quickmathfacts.com. There is no contact form and no account system, so email is the only way to reach the site.
Before you write
If you are reporting a problem, it helps to include the page address, the device and browser you used, and what you expected to happen. For a worksheet issue, mention the operation, difficulty and question count.
Privacy questions
Questions about data and privacy are covered by the Privacy Policy. In short: practice data stays in your browser and nothing is uploaded.
Corrections
If a generated problem or worksheet looks wrong, send the operation, difficulty and the exact problem. Reports help keep the generator accurate.