License
Short version: take the lessons, use them, credit the site. You do not need to ask, and there is no fee.
What is licensed how
Section titled “What is licensed how”| What | License | What that means |
|---|---|---|
| Lesson text, worked examples, figures and diagrams | CC BY 4.0 | Copy, print, translate, remix, use commercially. Credit the site and say if you changed it. |
| Code samples printed inside lessons | MIT | Use them in your own projects, including paid ones. Keep the notice. |
| The name, the logo and the mascot | Reserved | Not covered by either. Do not imply MBU endorses or accredits your thing. |
Two licenses rather than one because they are two different kinds of thing. An explanation of the chain rule and a working snippet of JavaScript get reused in different ways, and MIT is what a developer expects to find attached to code they are about to paste into a project.
How to credit
Section titled “How to credit”One line, anywhere sensible:
"Mom's Basement University" (momsbasementuniversity.com), CC BY 4.0Online, a link back counts as credit. On a printed handout, that line in the footer is enough. If you changed something, say so briefly - “adapted from” is fine. Nothing more formal is expected, and nobody is going to audit your worksheet.
For teachers and programs
Section titled “For teachers and programs”Use it in class. Print it, project it, assign a module, hand out the worked examples, rebuild a figure on a whiteboard. Translate it if your students need that. No fee, no permission needed, no license for anyone to sign, no form to fill in. Attribution is enough.
This applies to schools, tutoring centres, adult education, prison education, libraries, homeschool co-ops and anyone else teaching from it. Commercial use is allowed too: a paid tutor may teach from these lessons, and a paid course may include them, as long as the credit line travels with the material.
The one thing you cannot do is strip the attribution and present the work as your own. That is the only line here, and CC BY is the reason it is a short one.
Reuse questions go to echoesOTV@gmail.com, but for ordinary classroom use you do not need to write first. Just use it.
What this does not cover
Section titled “What this does not cover”The site’s own dependencies carry their own licenses, unaffected by anything here. Astro, Starlight and KaTeX are all MIT.
The mascot art and the logo stay reserved along with the name. They identify the site rather than teach anything, so they are the one part that would be confusing to hand over.
Mathematics itself belongs to nobody. Theorems, definitions and standard results are not claimed here - only the particular explanations, figures and code used to present them.
The full terms
Section titled “The full terms”Neither license is reproduced in full on this page, because the canonical text lives with the people who wrote it and a copy that drifts is worse than a link:
- CC BY 4.0 - plain-language summary and legal code
- MIT - full text, which is short enough to read in a minute
The repository also carries both, as LICENSE for the code and
LICENSE-CONTENT for the lessons.
See also the Terms of Use, which says the same thing in the place lawyers look for it.