This is an official ODERSA website. Here’s how you know

The official domain

The address of this site ends in odersa.org. Every service the association runs sits on a subdomain of odersa.org and nowhere else. If the address in your browser’s address bar does not end in odersa.org, this site is not ours.

Free, and no account

Everything is open straight away. No sign-up, no account, no password, no subscription, no advertising. Nothing is held back for those who pay, because there is nothing to pay for.

No data collected

This site does not follow you: no tracker, no tracking cookie, no measurement tool built into these pages, and nothing measured on your device. Our host counts requests in aggregate, as any server that answers does: a total, never a profile. You do not have to take our word for it: open your browser’s developer tools, go to the Network tab, and reload the page. You will see the full list of what the site asks for. Everything comes from odersa.org, nothing goes anywhere else.

Free to reuse

The content is published under the CC BY 4.0 license. You may copy it, translate it, print it and pass it on, for your classes as much as for the people around you, on one condition only: credit ODERSA.

A site by ODERSAA nonprofit association under French law (loi 1901) that makes education accessible to everyone, free of charge and with nothing asked in return.

Write to us

There is no form on this site, and that's deliberate: a form would send your words to an outside service. So you write directly, from your own email, to one of these two addresses.

Close-up of a thumb approaching the edge of a phone, not yet touching the screen.
An address, not a form.

What you can expect

  • A written reply from a real person, never an automated response.
  • Your address kept nowhere: there is no database, no newsletter, no mailing list.
  • A reported error fixed in the next content wave, and logged on the "What's new" page.

What we can't do

We do not take control of your device, we do not unlock an account, we give no individual financial or legal advice. For face-to-face help, a France Services center, a library, or a digital advisor in your town are the right doors to knock on.

Keyboard shortcuts

Tab
Move to the next item
Enter or Space
Tap the selected item in the exercise
Escape
Close the settings panel
?
Show this help