Trust
What we claim, and how you can check it.
How we decide that your child knows something, where each teaching method comes from, what is finished and what is not, and what happens to your family’s data. Every figure on this page is read from the app when the site is built.
How we measure
Built against false positives. “Not yet known” is a real answer.
A program that flatters a child is easy to build and useless to a parent. Ours is built the other way round: every idea starts as unknown, and the record only moves when the evidence does.
Missing evidence is never shown as zero, and never in green. If we have not seen enough, the brief says so and says what will happen next.
The rules are strict but not perfect. In simulation, 3.1% of learners who answer only 60% of questions correctly still reached Secure. We publish that rate rather than claim none.
- Not yet seen. No evidence yetNo evidence yet. Where every idea starts.
- Credited, not yet verified. Credited by placement because a later idea was shown; not yet verifiedPlacement saw a harder idea, so this one is credited and checked again later. Never shown as secure.
- Started. Has met this ideaMet in a lesson, or a first attempt made.
- Practicing. Practicing; not yet secureWorking on it, with evidence accumulating.
- Secure. Secure across formats and sessionsTwo good days: evidence in two sessions at least 20 hours apart, two kinds of question, and the last three answers right without hints. Fast guesses and revealed answers do not count.
- Mastered. Mastered: secure, transferred, and remembered after a weekSecure, then used on a real-world or proof question, and remembered a week later.
The 3.1% comes from simulated learners who answer 60% correctly, run through these rules. Those are simulated learners with research-default parameters, not children; real use may show the bar needs adjusting, and we will say so if it does.
Where each method comes from
Every choice is marked. Including the weak ones.
Like the assay mark on silver, a small stamp on every teaching choice says where it comes from: the Russian school, the American, or both in agreement. Open it and you see one sentence of why, and the strength of the evidence behind it.
Most of school mathematics has never been tested method against method. Where it has, we follow the evidence. Where it has not, the mark says so.
113 choices
61 choices
97 choices
What is finished
What exists today, and what does not yet.
Counted from the app at build time, 14 October 2026.
| Part | State | Detail |
|---|---|---|
| School ideas mapped, from first counting to the end of school | Done | 271 of 271, each with a guided brief and its place in the sequence |
| Full lessons in three lenses (See it, Use it, Prove it) | In progress | 58 of 271 school ideas (21%) |
| Practice questions, step-checked | In progress | 186 of 271 school ideas |
| Placement, daily sessions and spaced review | Built | Working in the trial today |
| The Family room and its weekly brief | Built | In the app; it is not sent by email |
| Fields: where the mathematics leads | Built | 15 careers and disciplines, 286 links to ideas |
| Beyond school (university horizon) | Mapped | 110 ideas mapped, as briefs only |
| Accounts, and progress across devices | Not yet | Progress lives in one browser; it can be downloaded and moved by hand |
| Payments | Not yet | Billing is not open; reserving a plan costs nothing |
| Children’s-privacy (COPPA) review by counsel | Not yetDone | Answer-level records and Google Analytics stay off inside the app until it is complete |
| An outcome study | Not yet | No child has completed a year with us; we plan one with founding families |
| Browsers tested | In part | Automated tests run in Chromium, the engine of Chrome and Edge; Safari and iOS are not yet tested |
Privacy, in plain words
Your child’s work stays with you.
- Without an account, your child’s name, answers and progress are kept in your browser, on your device. They are not sent to us.
- A family account is optional and belongs to a parent; children have no logins. With one, each child’s first name, age and learning record are kept on our server for your family alone, until you delete them. We never ask for a child’s surname, birthday, school or photograph.
- We count how the site and app are used, without names and without anything typed. Inside the app the counts are anonymous, and Google Analytics is switched off there.
- If you reserve a plan, we keep your email and the answers you chose, outside the public website, and delete them when you ask.
- We sell nothing and share nothing for advertising.
The guarantee
Try it first. Then a month to be sure.
- Trial
- 14 days of the full app, with no account and no card.
- Guarantee
- A full refund if you write within 30 days of your first payment. No questions you have to answer.
- Cancel
- The monthly plan at any time. Your child’s progress is always yours to download.
- Price
- Founding families keep their price while they stay members. Family is $49 a month, every child included.
Billing is not open yet, so there is nothing to refund today. The guarantee applies from the first payment.
Who is behind it
One founder, and an open address.
0 to 100 is new, built by one founder, Andrew, and it carries no advertising. Write to us and he reads it and replies, usually within a week.