Version 1.0.0 · effective 12 September 2026 · part of the Terms of Service
Learners aged 13 and over with an account. Younger learners can read and solve community problems and cannot post, vote or flag. Each account may submit up to 5 problems a day.
Problems you wrote, with a worked solution, on any mathematics. Write the problem in your own words. Do not paste a problem from a textbook, a past paper or a competition unless the source has released it for reuse; citing "in the style of AMC 10" is fine, reproducing an AMC problem is not. No personal information about anyone, no links to sites that sell answers, and nothing the Acceptable Use Policy forbids.
You keep ownership. You give Erudia a non-exclusive, royalty-free, worldwide licence to host and display your problem, format it for accessibility and different screens, and include it in problem sets, and to let the providers that run the service do those things for us. The licence ends when you delete the problem or your account, except that a problem already in a set other learners are practising stays there with your name removed, so that one deletion does not break someone else's practice queue. We never use your name or your problem in advertising without your written permission.
New problems are reviewed before they are published. A moderator may edit for clarity, decline, or remove a problem. Every decision to decline or remove comes with a written reason to you, and you can ask for it to be reconsidered by replying or by emailing erudia@erudia.org. Anyone can report a problem with the flag control; a report tells us what is wrong and where, and the reporter and the author both hear what we decided.
If you believe content on Erudia infringes your copyright, send a notice to erudia@erudia.org, or use the notice form. A notice must contain:
We act on a complete notice promptly, remove or disable the material, and tell the person who posted it, with a copy of the notice. A person who knowingly misrepresents that material is infringing is liable for the damages that result, including our costs and the poster's.
We have not yet registered a designated agent with the United States Copyright Office; we offer this process voluntarily and will register the agent before community problems are published to the public.
If your content was removed and you believe that was a mistake or a misidentification, send a counter-notice to the same address with: the material and where it appeared; a statement under penalty of perjury that you have a good-faith belief it was removed by mistake or misidentification; your name, address and phone number; your consent to the jurisdiction of the federal court for your district (or, if you are outside the United States, the Northern District of Illinois) and to accept service from the person who sent the notice; and your signature. We forward it to the complainant and restore the material between 10 and 14 business days later unless they tell us they have filed a court action.
We keep a log of every notice and what we did. An account that receives 2 substantiated notices within 12 months loses the right to post; 3 ends the account. A notice withdrawn or answered by a successful counter-notice does not count.
If you are in the European Union and believe a community post is illegal under EU or your national law, you can use the same notice form, choosing "other illegal content". Tell us why you think it is illegal, where it is, and how to reach you. We decide without undue delay, tell you and the author what we decided and why, and both of you can ask us to reconsider.
Erudia's lessons cite the contest and year of any competition problem they teach from, as a fact, and rewrite the problem in Erudia's words with different values where the mathematics allows. If you are a rights holder and believe a lesson goes further than that, the notice process above applies to us as it does to anyone.