What it teaches
That brackets decide what happens first, and that this changes the result. (3 + 4) × 2 is 14 and 3 + 4 × 2 is 11. Nothing about the numbers changed.
This is the first rule in maths that is a convention rather than a fact about quantity — and children accept it much more readily after they have seen the two answers side by side than after being told the rule.
How it works
An expression appears with brackets in it and a number pad underneath. The child works out the inside first and then the rest.
When the answer is wrong, the help does not restate the rule. It shows the bracket being worked out on its own line, so the expression becomes two smaller sums the child can already do. Only after that does it show the answer.
What to look for
This belongs to the last level of the maths games and to klasa IV in the Polish curriculum. A seven-year-old who wants to try it will not be harmed by it, but the arithmetic inside the brackets has to be secure first, or the child is fighting two problems at once.
The most common mistake is doing the sum left to right and ignoring the brackets entirely. If that is what is happening, the answer will be consistently wrong in the same direction, which is easy to spot.