Contact

One address, read by a person:

echoesOTV@gmail.com

There is no form, no ticket number and no chatbot. It is a mailbox.

A mistake in the math. This is the most useful message you can send and it goes to the front of the queue. Tell us the lesson and roughly where — “the third worked example” is plenty. If a figure disagrees with the text beside it, that is a real bug and we want it.

A broken page. Something not loading, a diagram that never appears, a quiz that will not submit. Mentioning your browser and whether you are on a phone helps a lot.

Account or data deletion. Email from the address you registered with and say you want the account gone. See the Privacy Policy for what that removes.

Requests to reuse content. Usually you do not need to ask. The lessons are openly licensed and attribution is enough — see the License page for the credit line and what it covers. Write if your situation is not covered there.

Suggestions for new subjects or lessons. Read and appreciated, but the queue is long and this is not a full-time operation.

Institutional enquiries. Schools, libraries, adult education and other programs: read, and answered when there is time. If you only wanted permission to teach from the lessons, the license already gives it to you and you can start without waiting for a reply.

Homework. We cannot do your assignment, sit your exam, or check your answers one by one. The lessons and their worked examples are the help on offer, and they are free.

Advertising and sponsorship enquiries. The site carries no advertising and no sponsorships, and no ad space is for sale.

Anything to do with paying for this. This site is not taking payments. There is nothing to buy, no subscription, no tip jar and no fundraising campaign, so there is nothing to discuss and no invoice to chase.

Usually a few days. Sometimes longer. This is a free site maintained around a job, so patience is genuinely appreciated — and a clear subject line helps more than a follow-up.