What to report
- A wrong formula or symbol, a missing unit, broken sub/superscripts
- An incorrect answer or explanation in an example or exercise
- A figure that disagrees with the text
- An inaccurate or awkward translation
- Broken layout, buttons that do not respond, images that fail to load
What makes a report useful
Include these three things and we can find the problem much faster:
- The page URL (copy it from the address bar)
- The exact spot, e.g. “the explanation under example 2” or “exercise 3”
- What you believe the correct result is, or a screenshot
Response time
We usually verify and reply within 3–5 working days. Rewrites or cross-language updates may take longer.
Report template
Page URL: Where: What is wrong: Suggested fix: Contact (optional):