About

Daily mental-arithmetic games, and a growing library of techniques you can practise rather than just read.

What it will never have

No accounts. No email capture. No ads, no affiliate links, no sponsored technique pages. No cookies, so no banner to dismiss. No profile of you, here or anywhere else. No streaks — a day off costs you nothing.

What it does with your data

Which puzzles you've solved and how long you took never leave your browser. They live on the device you played on, and you can export or delete them at any time. There is no server to send them to — the site is a set of files, with nothing running behind it.

Page views are counted, without cookies and without anything that follows you between visits or between sites. The count knows a page was loaded and roughly which country from; it cannot be tied to you, and it is never joined to your progress, which the counter has no access to. That is the whole of it, and it is why there is no cookie banner to dismiss. The long version is the privacy policy, which is not much longer.

For teachers

It's a URL you can put on a projector. Contrast is set for the back of the room, every control is at least 48px, and the technique pages work with JavaScript switched off — which some school devices do.

Corrections

If a puzzle looks wrong or a technique page has an error, that's worth knowing about — hello@boscelli.com.