What a ten-year-old is working on
Arithmetic that is finished being learned and needs to be kept: brackets, fractions, two-step problems. Geography with real detail in it โ the small countries rather than the obvious ones. And reasoning that is not arithmetic at all, which is where the logic games earn their place.
The algorithms
Line them up is bubble sort performed by hand: the only move is to swap two neighbours, and the number of swaps it takes is exactly the number of pairs that started out the wrong way round. Move the tower is the Towers of Hanoi, which is the shortest honest example of a plan that contains itself. Both have a Watch button that runs the algorithm a step at a time, and at ten a child can follow it.
What is not here
This site stops at ten. Long division, decimals, percentages and algebra proper are not on it and are not coming: a site that tries to cover five to sixteen covers none of it well. What is here is meant to be finished and then left.