Privacy

What we never collect

• No names, ages, email addresses, school names or classes.
• No accounts and no passwords. There is nothing to sign up for.
• No cookies of any kind — not for tracking, not for preferences.
• No advertising, no ad networks, no retargeting and no data brokers.
• No social media buttons, embeds, comment widgets or share trackers.
• No fingerprinting, and no device or advertising identifiers.

What is stored, and where

Progress is kept in your own browser, using a feature called local storage, under a single entry named mgc.progress.v1. It never leaves the device and it is never sent to us, because there is no server to send it to — this is a site of plain files.

That entry holds only:

• which levels have been attempted, and the stars earned on them;
• the best score and best time on each;
• how many attempts each has had;
• a day-counter streak, and the day the profile started.

Dates are recorded to the calendar day only — never a clock time — because a finer timestamp would say when a particular child was sitting at a particular computer, and that is not something a maths worksheet needs to know.

Clearing your browser's site data erases it completely. We cannot recover it, because we never had it.

Moving progress between devices

A progress code is a short piece of text that stands for the record above. You can copy it from one device and paste it into another. It is generated in the browser, it travels only by whatever means you choose to move it, and it passes through nothing of ours on the way. It contains no name and nothing that identifies a person.

What the site loads from elsewhere

Nothing that a page needs in order to work comes from another company. Fonts, images, stylesheets, games and worksheets are all served from this site. There are no content delivery networks and no external font services, which also means no third party gets to see your address simply because you opened a page here. That rule is enforced by an automated check that fails the build if anything external creeps in.

One exception is permitted: Cloudflare Web Analytics, which counts page views. It sets no cookies, records no personal data and does not follow anyone between sites. It is the entire measurement stack, it is the only third-party script this site is allowed to load, and it is absent from any build where it has not been deliberately enabled.

The games include two adopted from other open-source projects. Both were read line by line and stripped of anything that reached outside this site before they shipped; their licences and source are recorded on their own pages.

Working offline

Pages you have opened are saved on your device so they still work without a connection. That copy is held by your browser, on your machine, and is cleared with the rest of the site data.

Hosting and server logs

Like every website, the servers that deliver these pages keep ordinary technical logs — the address requested and the network address it was requested from — which is how a web server works at all. They are used to keep the site running and are not combined with anything else, because there is nothing else to combine them with.

Questions

If something here is unclear, or you think the site is doing something this page does not describe, please say so — a page like this is only worth anything if it is accurate.