About this site

I tutor about sixty students a year for Math Kangaroo, and I kept running into the same wall.

A student does a practice paper, scores 68 out of 120, and neither of us learns anything we can act on. “Study more” is not a diagnosis. I was doing the diagnosis in my head, every session, for every student, and it did not scale past the people sitting in front of me.

So this site is that diagnosis, made into software.

The Skill Atlas is the spine: 91 named skills — things like counting by position, nets and folding, invariants — grouped into seven strands and joined by prerequisite arrows. Each one has its own page: what it is, the phrases that tell you it is showing up in a problem, the mistakes students actually make, and a ladder of practice at the 3-, 4- and 5-point difficulties the real exam uses.

The problem bank is entirely original, and that part matters enough to say out loud. Math Kangaroo’s papers are copyrighted, so I do not host them. I link to their official free PDFs and publish my own skill index of them — “2019, level 5–6, question 22 tests these two skills”. Everything else here is a problem I wrote. That constraint is what made this real work rather than a link farm.

The explanations are the part I have not seen anywhere else. Writing a problem is easy. The hard part is writing five answer choices where each wrong one comes from a real mistake a real student makes — and then storing that mistake next to the choice. So the feedback is written for your error, not the average one. There are 708 of those explanations so far.