Robols Math

A short tour of the site: solving a problem from start to finish, how a problem's difficulty and rating are set, what is in the archive, the leaderboard and badges, and how to contribute a problem of your own.

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Robols Math is for mathletes preparing for local, regional and international competitions, and for enthusiasts who simply enjoy the problems. Established in 2019, it has grown into a small global community known for sharing challenging problems and working through the solutions together.

This site is a revival of — and a considerable improvement on — a website Robols used to run. The objectives are unchanged: share problems, discuss solutions with the community, and learn together. Where the older version was limited, this one makes contributing far easier: problems come from Robols and from solvers who propose their own, and each one is reviewed before it is published.

Each category has its own colour, used consistently everywhere — the bar beside a problem, its tag, your mastery chart, your activity feed. The bar's height shows difficulty; its colour shows the category. Brass is reserved for rating and rank, and never means anything else.

Both you and every problem carry a rating on the same scale, starting at 1000. Each problem you take on counts as a single game between the two of you: solve it and you win, abandon it and the problem does.

Problem ratings are recalibrated daily, from the difficulty ratings the community submits and from how people actually fared on it. Each result counts with the rating of the person who produced it, so a strong solver missing a problem says more than a beginner missing it, and a solve after a wrong answer counts for less than a first-try solve.

Your own rating moves the moment you finish a problem, one problem at a time. Beating a problem rated near you moves your number meaningfully; beating one far below you barely registers, while losing to it costs a great deal. A solve is always worth something, however easy the problem was. Overnight it can settle a little further, because a problem whose difficulty the archive has since learned more about is worth re-measuring you against. When that changes your rating, you get a notification saying by how much.

The rating you see is the season's rating. It starts again each season, which is what the next section is about.

The site runs in seasons, one per quarter. Season 1 ran to 30 September 2026; Season 2 opens on 1 October and every season after it begins on the first day of a quarter.

At each changeover every rating is placed rather than wiped. Where you finished decides where you land in a band from 900 to 1100: the season's best solver starts at the top of it, the rest are spread underneath in the order they finished. Everybody therefore starts a season close together, and the field separates again over the first weeks as problems are solved. Your all-time rating is kept and keeps running underneath, out of sight; it is what the archive's difficulties are calibrated against.

Your season rating carries a tier, shown as a mark beside your name wherever you appear.

Nothing is locked. Whatever your rating, every problem in the archive will take your answer, at any point in the season. A problem well above you costs you almost nothing if it beats you and is worth a great deal if you beat it, so there is no reason to keep you out of it. The problem of the day is still chosen for your level, as a suggestion rather than a limit.

Your profile shows the season being played, with every season you have finished behind a button, and the rating chart marks where one season ended and the next began.

A rating says how well you do per problem and nothing about how many you have done. A solve count says the opposite. The leaderboard is ordered by an overall score that puts four things together instead, each counted within the season:

The four are measured in different units, so each is first turned into a z-score: how far above or below the field you are in that part, in a unit all four share. Zero is the average solver of the season, positive is above it. The four are then combined in the proportions above.

Because it is a standing in a field rather than a total, your score moves when other people solve, and the gaps between solvers are real rather than flattened into places. How the overall score works sets it out in full.

Rating says where you stand relative to other solvers; XP says how much you've done. Rating can fall while XP only accumulates.

Every problem carries a difficulty from 1 to 10, and XP scales super-linearly with it: a difficulty-10 problem is worth roughly thirty times a difficulty-1 one.

Three multipliers adjust the XP a problem awards: the number of attempts you took, your solving time, and your current problem streak.

Solving earns badges — twenty-eight of them, covering volume, mastery of each category, hard problems, precision, timed tests and quiz bees, and contribution to the archive. Most come in five tiers, so The Committed marks ten problems solved at tier I and five thousand at tier V.

They are worked out from your record rather than stored, so a badge always matches the figures beside it, and they are counted over everything you have ever done rather than over the season: a badge is reached once and kept. Rising Star, Master, Grandmaster and Immortal used to be badges here and are tiers now, because where you stand this season is a different thing from what you have reached.

Your profile shows the ones you have earned; the full list of badges shows every one and what it takes.

The archive is built by the people using it. Anyone can propose a problem, and every proposal is reviewed before it is published — accepted ones are credited to you on the problem itself, and your solution becomes the first comment on it.

Smaller things count too. Rating a problem's difficulty is what the community difficulty is built from, and it is the only measure of a problem that comes from solvers rather than from the archive. Suggesting a topic, reporting a problem that is wrong, and writing a solution others find useful all shape what the site becomes.

Contribution points record that work on your profile: 5 for a problem accepted into the archive, 2 for a note or bug report that gets acted on, and 1 each for rating a problem, having a comment upvoted, getting a topic accepted, or filing a report that is upheld.

They are counted separately from rating and XP on purpose. Rating says how you perform and XP says how much you have solved; neither has anything to say about what you have given back.

Robols Math has been posting problems and solutions since 2019. Come and say hello.

What we collect. Account details you give us — name, email, and optionally birthday, gender, country and what kind of solver you are — plus your solving activity and anything you submit through Contribute.

What is public. Your username, country, season rating and tier, overall score, XP and profile picture appear on the leaderboard and beside your comments. Your email, full name, birthday and gender are never shown to other users.

What we use it for. Calculating your rating, tier and place on the board, choosing a problem of the day at your level, improving problem calibration from aggregate solve data, and occasionally writing to you about the site.

Email. Beyond the account mail you ask for, we write rarely — a season opening, a batch of new problems. Every one of those carries a link that stops them for good in one click, without signing in, and stopping them changes nothing about your account or your record.

What we don't do. We don't sell personal data, and we don't share it with advertisers.

Your control. You can edit your profile at any time from the Profile page, including clearing any optional field.

This is the short version. The full Privacy Policy sets out exactly what is collected, who processes it, how long it is kept and how to have it removed.

Using Robols Math means agreeing to the Terms and Conditions — how accounts work, what is expected in discussions, what happens to problems you contribute, and how moderation and bans are handled.