Sources & licensing
Original work, traceable sources.
A problem being visible online does not make it free to copy. Our content model tracks source, license, attribution, permission, and review status.
What we may use
Original authored problems, canonical mathematical questions, public-domain materials, and appropriately licensed sources.
What we do not scrape
Commercial solution manuals, Chegg, Course Hero, private course portals, current protected exams, or unauthorized test banks.
Independent expression
When a mathematical idea is common but source wording is protected or uncertain, we independently state the question and write an original solution where legally appropriate.