Free, open and private

The mathematics belongs to no one. Unless a page says otherwise, the writing and figures on Mathomaly, including screenshots of the explorations, are licensed under Creative Commons Attribution 4.0 (CC BY 4.0). You can copy, share and adapt them, in lessons, slides, articles, videos or anything else, as long as you:

• credit Mathomaly and link to the page you used, for example “From Mathomaly, mathomaly.com/explore/kaprekar”;
• say if you changed anything;
• do not suggest that Mathomaly endorses you or the way you use it.

Some things are not covered by that licence:

• material credited to someone else, such as quoted sources, which belongs to its owners;
• the Mathomaly name and logo;
• the videos, which stay under YouTube’s standard licence. Link to them and embed them freely, and use short clips to review, discuss or teach, with a credit and a link. For anything more, ask.

Your settings stay on your device. The colour theme, the motion setting and your saved investigations are kept in your browser’s local storage. They are never sent anywhere, and clearing this site’s data in your browser removes them.

Hosting. The site is served by Cloudflare. Like any web host, its servers see your IP address and the pages you ask for, and keep short-lived logs for security and to keep the site running.

Bigger calculations. A few explorations can hand a heavy calculation to a server run on Amazon Web Services. Only the numbers you chose are sent, and nothing that identifies you is stored with the answer.

Videos. The player on the Watch page loads nothing from YouTube until you press play. After that it uses YouTube’s privacy-enhanced mode, and YouTube’s own privacy policy applies.

The contact form. When you send a message, your words, and your name and email address if you give them, are emailed to me. I use them only to read your message and reply, I never add you to a mailing list, and I never pass them on. Ask and I will delete them. The form uses Cloudflare Turnstile to keep out spam, which checks your browser without a puzzle in most cases.

Mathomaly is run from Aotearoa New Zealand under the Privacy Act 2020. To ask what I hold about you, or to have it corrected or removed, use the contact form.

Every claim on the site is checked and labelled with how far it is established, as the method describes. Mistakes still get through, so the site is offered as it is, without any guarantee. It is here for learning and curiosity, and nothing on it is professional, medical or financial advice. If you find an error, please tell me.

Please do not try to overload the site or its calculation service, or use them to attack anything else. Links to other sites are there because they are useful; what those sites contain is up to them.

If these terms change, the date below changes with them.

Last updated 22 October 2026.