MIT OpenCourseWare
ocw.mit.edu
Publishes the real lecture notes, problem sets and exams from MIT courses
openstax.org
Peer-reviewed university textbooks you can read online or download as PDFs.
Rice University's open textbook programme: around eighty full titles across maths, the sciences, social sciences and business, each written and reviewed by academics and released under a Creative Commons licence. Every book has a web reader, a downloadable PDF and, for many, instructor answer keys. Coverage is first- and second-year survey courses, so it replaces the £70 introductory textbook rather than the specialist monograph.
Questions
Works the moment the page loads. No account, no email, no trial. Solution manuals and test banks need a verified instructor account, and printed copies still cost money.
Yes. OpenStax sends your input to its own servers to process it. That is fine for public material; for anything containing personal data, use one of the on-device tools instead.
Solution manuals and test banks need a verified instructor account, and printed copies still cost money.
Alternatives
Same category or same task, ordered by how closely they overlap.
ocw.mit.edu
Publishes the real lecture notes, problem sets and exams from MIT courses
monkeytype.com
A typing test you can tune to the exact words, punctuation and length you want
musictheory.net
Free lessons and endless drills for notation, intervals, chords and ear training
apps.ankiweb.net
Schedules flashcard reviews for the day before you would have forgotten them
duolingo.com
Turns a language into five-minute daily drills you will actually keep doing
exercism.org
Practice exercises in 80-odd languages with free feedback from a human mentor