Corrections

Educational material that nobody corrects rots quietly. Here is what we do when something turns out to be wrong.

The policy

• We fix it.
• We say what changed, and when, on this page.
• For anything substantive — a wrong answer, a milestone that misled someone — we say what was there before, rather than quietly editing and moving on.
• If you reported it and want credit, you get it. If you would rather not be named, you will not be.

Why this page exists

Every worksheet site on the internet claims its material is accurate. None of them show you what they got wrong. A visible corrections log is the cheapest honest signal available — it costs us nothing when we are right and a little embarrassment when we are not, which is exactly the incentive it should create.

Log

Nothing yet. This page went up with the site, so an empty log here means the site is new, not that it is perfect.

Found something? Tell us. If it is a worksheet, include the sheet code from the top corner.