Why Math Challenge exists
This page does not open with the product. It opens with children losing hours to TikTok, and with an adult who had not studied mathematics in twenty-five years and wanted to challenge his own mind again.
Two halves
The first half is about children and TikTok. Esteban Rey started from the number of children losing their time on TikTok and platforms like it, and thought about building something addictive enough to compete with that.
The second half is about him. He likes mathematics, and he had gone twenty-five years without studying it. So he thought about a game that could challenge his own mind. That explains something about the product that would otherwise look like overreach: why the ladder runs all the way to algebraic topology, and why there are adult clubs with challenges among friends. Those are not features bolted onto a children's product to widen the market. They are the owner's own use case. The adult who wants to come back to mathematics twenty-five years later is not a secondary segment — he is the person who started this.
The word was “addictive”, and the research contradicted it
That word is the literal origin of the brief, and it is the one the research spent the most effort contradicting. It is worth saying precisely what happened, because the easy version would be to hide it and the true version is better: the intent was never to exploit a child. It was to win attention back from something that already holds it. TikTok is the incumbent of children's attention. Wanting to compete with it is a legitimate goal, and very few educational products state it that plainly.
What the research showed is that you cannot beat TikTok by being more addictive — neither ethically nor legally. The EU's Digital Fairness Act is mid-legislative-process and explicitly targets addictive design and dark patterns. Standard 12 of the UK's Children's Code bars nudge techniques that push children to hand over more data or weaken their privacy settings. Loot boxes were ruled illegal gambling in Belgium and the Netherlands in 2018. And Prodigy Math — a school math game in the same category, for the same audience — drew a complaint before the US Federal Trade Commission in 2021 over membership advertising aimed at children who had started playing free at school.
There is a second finding, and it has nothing to do with regulators: several of the mechanics that hook a young child hardest are the ones the evidence ties to math anxiety, which is measurable from around age six. Identical arithmetic shows no anxiety effect on untimed paper and a substantial one under a clock. The clock is not incidental to the harm; it is the amplifier.
So the goal stayed and the method changed: not to be more addictive than TikTok, but to be the thing worth choosing. Every engagement mechanic with evidence behind it stayed. Every one with regulatory exposure was named and ruled out, in writing.
Mathematics always came easily to him
It matters to say so, because it changes where the product is written from. This is not the story of someone who suffered mathematics and wants to spare others. It is the story of someone it came easily to, and who for that reason watched from close up the ones who fell out along the way — and knows the difference was not only talent.
That is where a concrete stance comes from. The rules against shaming a child for being wrong, and against putting a clock on the youngest ages, do not come from a personal wound. They come from having watched the system lose people who were good at this.
What he is against
Charging a child to practice. Hearts, lives, energy that runs out. A child who wants to do mathematics and cannot, because the attempts ran out.
Hence the line that is not up for negotiation: practice is free forever. Nobody is ever charged for letting a child do mathematics. What is charged for is the support given to the parent, which is a different thing.
And there is a second half, in the positive: to use his own capabilities and those of Ignia Cloud to take a project that is good for everyone as far as it will go. It is not deliberately a small project. The technical ambition — seven locales, kindergarten to doctorate level, working on bad networks — is part of the point, not an excess.
What would make it worth it
That it reaches those who cannot pay.
Children in public schools, on congested networks, on old phones, in seven locales, at no cost. That being free is not a cut-down version of the product but the product itself.
That turns several technical decisions into moral ones, and they are worth seeing together:
- The performance budget on a low-end Android phone is not an optimization. It is the condition for that sentence to be true.
- HTTP/3 matters precisely for the user that sentence names: on a lossy mobile connection, one dropped packet no longer stalls every request on the page. It is checked against the live site, not assumed.
- The seven authored locales are expensive exactly because of this. Five languages, seven locales: Mexico is the only Spanish-speaking country that writes the decimal point, and Portugal and Brazil do not share the same numeric scale. Treating “es” or “pt” as one thing produces mathematically wrong content that nobody notices.
What publishing this forbids
Publishing this has consequences, and it is honest to write them down next to the story.
- We cannot claim it teaches until there is a study of our own, with pre/post measures and delayed retention. On a site that makes a point of rigor, a single unsupported claim costs more than elsewhere.
- We cannot boast infrastructure that is not ours. Math Challenge is a project by Ignia, and it runs on Cloudflare. The two statements are made separately, and both can be checked.
- We cannot hide the word “addictive”. It is in the origin, the research contradicted it, and the product changed. Telling it in full is stronger than leaving it out — and it is what separates a site with evidence from a site with marketing.
- Being free stops being a pricing decision and becomes a public promise. If this product ever charges a child to practice, this page is the document that contradicts it.
No grander story than this
A guy who was good at mathematics, who watched others left outside, who cannot stand a child being charged to practice, and who has the means to do something about it. That is enough.
Math Challenge is in construction. Nothing on this page describes a released product: it describes the decisions the product is being built under.
Where this comes from
This page is written from an interview with the owner. The interview, the research it cites (mc-10 on math anxiety, mc-17 on gamification and dark patterns, mc-34 on locales and notation, mc-47 on performance and protocols) and the decision log it cites (D-014 on gamification, D-021 on monetization, D-022 on locales, D-033 on this site) are all public in the repository.