Contact

The best way to reach us is by email: [email protected].

We are glad to hear about

• mistakes in a lesson, example, calculator or simulator — please include the page address and what looks wrong;
• topics or languages you would like to see next;
• account or privacy requests (please write from the email address on the account);
• anything that does not work on your device or browser.

We read every message, although we cannot always reply individually.