Errata
Corrections
When a published card is wrong, or gets updated in a significant way, the fix is recorded here with the date and what changed.
Log
The first one will appear here, newest at the top.
What counts as a correction
A wrong date, a wrong attribution, a formula or definition that does not match its source, a step that leads you astray, or a claim the source does not support. Each is logged with what the page said before and what it says now.
Typos, rewording, and new examples are fixed without an entry. The “Last updated” date at the bottom of each card still changes as they get updated.
Report something or get in touch
Tell us which card and which sentence needs to be updated, and where the right answer can be checked. A link to a primary source is the fastest way to a fix. Get in touch through the contact form: