Terms of Service

Last updated: October 10, 2026

By downloading or using Math Masters Formula Encyclopedia ("the App"), you agree to the following terms.

1. License

We grant you a limited, non-exclusive, non-transferable license to use the App on Apple devices you own or control, subject to the App Store Terms of Service.

2. Content

The mathematical formulas presented in the App are public domain mathematical knowledge. The explanations, analyses, and educational content are original works. You may use the content for personal learning and reference. Redistribution of the App's proprietary content (explanations, analyses, UI design) is prohibited.

3. Free Access, Rewarded Ads, and Pro

• Preview: Every formula can be browsed, but its full details, tutorial, derivation, and exercises stay locked until it is unlocked.
• Rewarded ad: Watching one advertisement to completion permanently unlocks one formula on that device. A maximum of five new formulas can be unlocked this way each day. The unlock is stored only on the device and is not restored if the App is deleted or you change devices.
• Monthly Pro ($2.99): Unlocks all current formula content and removes rewarded ads for one month. It renews automatically unless canceled at least 24 hours before the end of the period.
• Yearly Pro ($19.99): Provides the same Pro access for one year and renews automatically under the same cancellation rule.
• Lifetime Pro ($39.99): A one-time purchase that permanently unlocks all current and future formula content and removes rewarded ads.

Prices shown above are the United States base prices. The App Store displays the applicable local price before purchase. All purchases are processed by Apple. Refund requests should be directed to Apple Support. If a subscription expires or is refunded, formulas previously unlocked with ads remain unlocked on that device.

4. Auto-Renewable Subscription Terms

• Subscriptions offered: Monthly Pro (length: 1 month, $2.99 per month) and Yearly Pro (length: 1 year, $19.99 per year). Prices are United States base prices; the App Store shows the applicable local price before you confirm.
• Payment: Payment is charged to your Apple ID account at confirmation of purchase.
• Automatic renewal: Your subscription renews automatically at the same price and for the same length unless you cancel at least 24 hours before the end of the current period. Your account is charged for renewal within 24 hours before the end of the current period.
• Manage or cancel: You can manage your subscription and turn off auto-renewal at any time in your Apple ID account settings (Settings > your name > Subscriptions) after purchase. Deleting the App does not cancel a subscription. Canceling takes effect at the end of the current paid period, and no refund is given for the unused part of that period except as required by law or decided by Apple.
• Free trial: If a free trial is offered, any unused portion of it is forfeited when you purchase a subscription.
• Restore: You can restore previous purchases on a new device through the Restore Purchases option in the App, signed in with the same Apple ID.
• Price changes: If the price of a subscription changes, Apple will notify you and, where required, ask for your consent before the new price applies.

See also our Privacy Policy.

5. End User License Agreement (EULA)

Your use of the App, including its in-app purchases and auto-renewable subscriptions, is governed by Apple's Standard License Agreement (the "Standard EULA"): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/.

These Terms of Service supplement the Standard EULA. If these Terms conflict with the Standard EULA, the Standard EULA prevails to the extent of the conflict.

6. AI Features

The AI Q&A feature uses Apple's on-device Foundation Models. AI responses are generated locally and may not always be accurate. The App is not responsible for decisions made based on AI-generated content.

7. Disclaimer

The App is provided "as is" without warranty of any kind. While we strive for mathematical accuracy, we do not guarantee that all content is error-free. The App is intended for educational reference only.

8. Limitation of Liability

To the maximum extent permitted by law, we shall not be liable for any indirect, incidental, or consequential damages arising from your use of the App.

9. Changes

We reserve the right to modify these terms at any time. Continued use of the App after changes constitutes acceptance of the new terms.

10. Contact

For questions about these terms, contact us at: flashbody@foxmail.com