A fence is 12 metres long. Posts stand every 3 metres, including at both ends. How many posts are there?
|--3--|--3--|--3--|--3--|
School teaches how to solve a problem by an example worked in class. Olympiad problems teach how to find a way when there is no example to follow. Up to grade 6, a parent can prepare a child for them, and MathTrail is made for that.
Grades 1–6FreeOpen source
A school sum
You need to know how to divide.
12 ÷ 3 = 4
An olympiad problem
A fence is 12 metres long. Posts stand every 3 metres, including at both ends. How many posts are there?
|--3--|--3--|--3--|--3--|
Answer: 5Trap: 4 is the gaps, not the posts
You need to understand what is going on.
Olympiad problems have been set to children for more than a century, yet careful studies of what they do are few. These are four of them.
In Germany, third- and fourth-graders took a course of olympiad-style problems. At the Mathematical Olympiad they did clearly better than children who entered without the course, and the fourth-graders also did better on a school maths test. Their teachers had picked them for the course.
Brazil's maths olympiad for public schools is open to every pupil, and 19 million took part in 2009. Schools that entered it had better maths results among their ninth-graders on the national test, and better still the more years they had entered.
The higher a teenager scored at the International Mathematical Olympiad, the more often they went on to a doctorate, published research, were cited and won the highest prizes in mathematics.
How well six-year-olds reasoned logically foretold their maths 16 months later. Children who were taught to reason this way made more progress in maths than children who were not.
This is no reproach to school, which has a different job. But the knack of finding a solution when no method is given does not appear by itself. It is trained.
| A usual lesson | An olympiad problem | |
|---|---|---|
| How the problem is built | A method is shown, then repeated on similar examples | No method is given, and it has to be found |
| What counts | Working fast and without slips | Understanding what is going on, and explaining why |
| What a mistake means | A mark lost | A sign of where the reasoning turned the wrong way |
| What it teaches | To use a tool you know | To invent one when there is none |
A teacher has to bring every pupil up to the standard. Hours for problems beyond the syllabus are hard to find.
A test checks the result. There is seldom time to go through how a child reasoned, and where exactly it went wrong.
Not every school runs an olympiad circle, and the nearest one may be far away or take only older children.
The problems, their answers and the explanation of mistakes are MathTrail's part.
An olympiad problem is a puzzle, not a test. A child should be curious, not afraid of being wrong.
Not “to get top marks”, but to learn to invent a way when nobody has shown how.
A little time beside your child, better often than a lot at once. Your interest in a problem is catching.
Not by the number of problems, but by what happens around each one.
Every problem belongs to a topic, such as “Enumeration”, “Parity and alternation” or “Knights and liars”. The topics form a map, from the simple to the hard.
Every topic has a rating of its own. By it MathTrail chooses what comes next, the topic and the difficulty; the grade only sets the start.
Behind every wrong option stands a named trap. The explanation starts from how the child reasoned, not from the right answer.
A child can ask for a hint, or ask in their own words, “why not 6?”. The model answers about this very problem.
In a study of the apps that three-to-five-year-olds play, about two in three had designs that keep a child playing longer (Radesky et al., 2022). MathTrail is built differently, and that can be checked.
The model writes a problem and a program that solves it. The server runs the program in a sealed sandbox and checks that exactly one option is right, that the answer agrees, that the text suits the grade and that it does not repeat the text of earlier problems. A problem that fails never reaches the child.
MathTrail has no AI of its own. The problem is written by the model of your chat, within your plan, and Claude's free plan will do. The server has almost nothing to pay for, so there are no subscriptions, no ads and no locked topics.
The child's profile is a file in your Google Drive. Only the answer and the solution of the problem being solved are sealed, so that the child cannot peek. The server keeps nothing between requests and sells nothing.
No coins, no chests, no timers, no ads. Once the problem is solved, the chat can be closed and the problem talked over at dinner.
The code is open, and every claim this page makes about MathTrail can be checked in it.The code on GitHub
Connecting takes a few steps. The first problem is best solved side by side with your child.