C:Math Terms of Service

Last updated: 2026-05-29 · Effective: 2026-05-29

1. Acceptance of Terms

By accessing, browsing, or otherwise using the website located at c-math.net (the "Service"), you acknowledge that you have read, understood, and agree to be bound by these Terms of Service ("Terms"). If you do not agree to any part of these Terms, you must discontinue use of the Service immediately. These Terms form a legally binding agreement between you (the "User") and the operator of C:Math (the "Operator"). The Operator may update these Terms periodically, with the most recent revision date displayed above. Continued use of the Service after such updates constitutes acceptance of the revised Terms.

2. Eligibility

The Service is open to users of all ages worldwide. However, in accordance with the Korean Personal Information Protection Act and analogous regulations such as COPPA in the United States and GDPR-K in the EEA, minors under fourteen (14) years of age should use the Service only under the supervision of a parent or legal guardian. Users are responsible for ensuring that their use of the Service complies with all applicable local laws and regulations in their jurisdiction. The Operator reserves the right to restrict access from jurisdictions where the Service may violate local laws.

3. Service Description

C:Math is a free, browser-based educational tool that provides interactive practice problems across six mathematical domains: matrix operations, vector calculus, arithmetic, geometry, statistics, and probability. The Service includes real-time automated grading, optional user accounts for progress tracking, a global leaderboard, exportable offline worksheets, and a bilingual Korean and English interface. The Operator may add, modify, or remove features at any time without prior notice, though reasonable effort will be made to preserve user data continuity.

4. Account and User Data

Creating an account is entirely optional; visitors may solve problems without registering. Account creation requires an email address, a display name, a password, and a security question. Passwords and security answers are hashed using the bcrypt algorithm and are never stored in plaintext. Learning records such as accuracy, solve time, and progression are linked to the account. Users may delete their account and all associated data at any time from the settings panel; deletion is immediate and irreversible. For complete details, see the Privacy Policy.

5. Permitted Use

Users are encouraged to use the Service for the following purposes: personal study and self-paced learning; classroom and tutoring use (with attribution to C:Math welcomed); sharing of results, scores, and screenshots on social media or academic forums; embedding linked references in non-commercial educational materials; and printing offline worksheets for personal or classroom distribution. Teachers and instructors are explicitly permitted to assign problems generated by the Service as part of their curriculum without prior permission.

6. Prohibited Use

The following activities are strictly prohibited: automated large-scale scraping or crawling of generated problems and answers; any attempt to overload, degrade, or disrupt Service availability, including denial-of-service attempts; reverse engineering, decompiling, or otherwise probing the authentication or anti-cheat subsystems; circumventing or tampering with HMAC-signed payloads used to validate scoring integrity; redistributing the Service or its content as a commercial product, paid course, or paywalled resource; and impersonation of other users or fraudulent leaderboard manipulation. Violations may result in immediate account termination and, where applicable, legal action.

7. Advertising and Third-Party Services

The Service is supported by display advertising provided by Google AdSense. Third-party vendors, including Google, may use cookies, web beacons, and similar tracking technologies to serve advertisements based on a user's prior visits to this site and other sites on the internet. Google's use of advertising cookies enables it and its partners to serve interest-based ads. Users in the European Economic Area, the United Kingdom, and Switzerland are presented with a Google Funding Choices consent banner upon arrival, where they may grant or deny consent to personalized advertising and tracking. Users may opt out of personalized advertising at any time by visiting Google Ads Settings at google.com/settings/ads. The Service also uses Google Analytics and Google Tag Manager for traffic measurement, Supabase (PostgreSQL) for account and learning-record storage, and Netlify for static hosting and serverless functions. Each of these providers operates under its own privacy policy, and the Operator is not responsible for their independent practices.

8. Intellectual Property

All original content on the Service, including the problem-generation logic, explanation text, user-interface copy, visual design, and source code, is the intellectual property of skskdustn and is protected by copyright laws of the Republic of Korea and international treaties. Mathematical concepts themselves are not copyrightable; users may freely cite, reproduce, and discuss concept explanations with attribution. The Service is built atop several open-source dependencies whose licenses and credits are acknowledged on the About page. Trademarks, logos, and brand names used on the Service that belong to third parties remain the property of their respective owners.

9. Disclaimers

The Service is provided strictly as an educational and practice tool and does not constitute professional tutoring, academic certification, or qualified mathematical advice. While the Operator makes reasonable, best-effort attempts to ensure correctness of generators and answers, no warranty is made regarding accuracy, completeness, or fitness for any particular purpose. Users are strongly encouraged to independently verify any calculation that influences academic, financial, scientific, or safety-critical decisions. The Service is provided "as is" and "as available", without warranties of any kind, whether express or implied, including merchantability, fitness for a particular purpose, and non-infringement.

10. Limitation of Liability

To the fullest extent permitted by the laws of the Republic of Korea, the Operator shall not be liable for any indirect, incidental, consequential, special, exemplary, or punitive damages — including but not limited to loss of data, loss of academic opportunity, loss of profits, or loss of goodwill — arising out of or in connection with use of, or inability to use, the Service. The Operator's aggregate liability for any direct damages shall in no event exceed the amount paid by the user to the Operator for the Service, which, given that the Service is free of charge, is zero Korean Won (0 KRW).

11. Termination

Users may terminate their account at any time through the settings panel; data deletion will occur immediately upon confirmation. The Operator reserves the right to suspend or terminate any account that violates these Terms, abuses the Service, or otherwise harms other users or the integrity of the leaderboard. Where reasonably possible, the Operator will provide prior notice via the registered email address; however, in cases involving security incidents or active abuse, termination may occur without notice. Upon termination, the relevant provisions of these Terms regarding intellectual property, disclaimers, limitation of liability, and governing law shall survive.

12. Governing Law

These Terms shall be governed by, and construed in accordance with, the laws of the Republic of Korea, without regard to its conflict-of-laws principles. Any dispute, controversy, or claim arising out of or relating to these Terms or the Service shall be submitted to the exclusive jurisdiction of the courts located in Seoul, Republic of Korea. Users outside Korea acknowledge that they are voluntarily submitting to this jurisdiction by continuing to use the Service.

13. Changes to Terms

The Operator may revise these Terms from time to time to reflect changes in features, applicable law, advertising practices, or operational policies. Material changes will be announced via a prominent banner on the homepage, an in-app notification on next sign-in, or both, with at least seven (7) days of advance notice where feasible. The "Last updated" date at the top of this document will always reflect the most recent revision. Continued use of the Service after the effective date of any revision constitutes acceptance of the revised Terms. Users who do not agree with a revision should discontinue use and may delete their account.

14. Contact

For questions, complaints, or legal notices regarding these Terms, please write to rin238238@gmail.com. See also the Contact page for general inquiries, bug reports, and feature requests. Korean-language correspondence is welcome and will receive equal priority.