OANA RINALDI · GOLDBACH

Privacy, simply explained.

Goldbach’s Conjecture Math is an educational app for exploring prime numbers. It does not require an account, display advertisements, use tracking technologies or send your calculations or learning activity to us.

Last updated: 26 October 2026.

What stays on your device

Calculations, history, favorites, lesson completion, bookmarks, practice answers and streaks are saved locally on your Apple or Android device. Lessons and mathematical explorations work offline. Learning progress does not sync through an app-operated cloud service. On Apple devices, backups may include app data according to your Apple backup settings. The Android app disables cloud backup and device transfer of its local data.

Goldbach Plus subscriptions

The existing calculator, history, favorites and result sharing remain free. Five introductory lessons, the daily question and the prime sieve are free. Optional Goldbach Plus monthly and annual subscriptions unlock all 30 lessons, unlimited practice, the Ulam spiral, prime-gap charts, the Goldbach atlas with CSV export, and the factor explorer. Both plans provide the same access.

Apple handles payment, billing and subscription management on iOS. We do not receive or store your payment-card information. The app uses Apple’s StoreKit framework to check verified subscription entitlements. Store access, purchase and restore operations communicate with Apple under Apple’s privacy policy. Apple may provide developers with sales and financial reports through App Store Connect; we do not link these to your local learning data.

The price and billing period are shown before purchase in your local currency. Payment is charged to your Apple Account on confirmation. Subscriptions automatically renew unless canceled at least 24 hours before the current period ends. You can manage or cancel a subscription in your Apple Account. Canceling stops future renewal; access continues for the remaining paid period. Deleting the app does not cancel a subscription. Use Restore Purchases in the app to recover active access for the same Apple Account.

On Android, Google Play handles payment, billing and subscription management. The app uses Google Play Billing to query available plans and active subscription access, process purchases and restore access. These operations communicate with Google under Google’s privacy policy. We do not receive or store payment-card information and do not send your local calculations, lesson progress or practice activity to Google. Google may provide developers with purchase and sales reports; we do not link these to your local learning data.

Google Play Billing may automatically send technical diagnostics about billing API successes, failures and service connection issues to Google, together with technical app and device context. Google uses this information to operate and improve its billing service. We do not receive these diagnostic logs. The app does not send its calculation history, lesson progress, bookmarks or practice answers as part of these diagnostics.

Android prices and billing periods are shown in your local currency before purchase. Payment is charged to your Google Play account at confirmation. Subscriptions renew automatically unless canceled. Manage or cancel in Google Play; access continues until the end of the paid period. Deleting the app does not cancel a subscription. Restore Purchases checks active access for the same Google Play account. Apple and Google Play subscriptions are separate purchases and do not transfer between platforms.

Sharing and exports

When you choose Share or Export CSV, you decide which app, person or storage destination receives that content. It is not automatically uploaded to us. External links open the selected websites, whose own privacy policies apply.

Your choices and deletion

You can clear calculation history and favorites in their tabs. Learn → Progress → Reset learning progress removes lesson completion, bookmarks, practice statistics and streaks from this device. Deleting the app removes its local app data; any Apple-managed backups are controlled through your device settings. There is no developer-operated account to delete.

Children’s privacy

We do not knowingly collect personal information from children or other users through the app. Purchases use Apple’s or Google Play’s purchase and parental controls, where configured by a parent or guardian. No public profiles, messaging or user-generated content are included.

Terms of use

Subscriptions and app use are covered by Apple’s Standard End User License Agreement on iOS and Google Play’s Terms of Service on Android. The app is an educational exploration tool. Numerical experiments do not prove Goldbach’s conjecture. Large-number primality results may be probable-prime results rather than certificates.

Support

For questions, purchase help or privacy requests, contact Oana Rinaldi at oanaunciuleanu@gmail.com. If you email support, we receive the information you choose to send and use it to respond. Please avoid sending payment-card details.