Five problems. Once a day. The same five for everyone.
A small daily weighing-up of mental arithmetic — for people who would rather not do mental arithmetic.
Every day at midnight UTC one ladder of five problems is generated, and it is the same ladder for everyone on the planet. You get one attempt. A wrong answer ends it — and that is fine, because the thing being recorded is that you turned up, not that you were perfect.
No timer on the screen
Visible time pressure measurably degrades performance in people who are anxious about maths, which is exactly who this is for. Your time is recorded quietly and shown to you later, never while you are thinking.
Missing a day is free
Rest days are automatic and cost nothing. There is no streak to buy back, no notification that tells you what you have lost, and no countdown.
The whole back catalogue
Every past day stays playable, free and uncapped, alongside eight practice paths you can drill one skill at a time.
What it will and will not claim
Ponderanda does not make you smarter. It will not improve your focus, your memory, or your general intelligence, and anyone selling you a puzzle that does is describing something the evidence does not support.
What it can do is narrower and actually measurable: you get faster at arithmetic you practise. After enough days the app will tell you by how much — and it stays quiet until it has enough data to say something true, which takes about two months of playing.
Where your data goes
Almost nowhere. There is no account, no sign-in and no sync. Your solve history, your streaks and your settings are stored on your own device and are never uploaded.
When you finish a day, the app adds one to a counter so it can tell you what share of players stopped at the same problem. That counter carries no identifier of any kind. The full detail is in the privacy policy.
Coming to Android. Ponderanda is in development. The Android app is free, and there are no ads at all while you are solving the daily ladder — that part is permanent.