The parent comment is exactly spot on. Those are exactly the right resources. If you are working with a gifted math student, 100% bookmark it and follow up soon. AoPS has a ton of excellent books for coursework and also just deeper problem solving (billed as competition problems).
In fact, even if you do not have a "gifted" youngster, learning to work on harder problems is so much better than learning to follow instructions by rote. Not to say all teaching is that way, but it seems like a majority.
Another resource is MOEMS, the Math Olympiads for Elementary and Middle Schools. They are totally reasonable and also fascinating problems. Get one of the books and check it out if you are working with someone in the late elementary.
In fact, even if you do not have a "gifted" youngster, learning to work on harder problems is so much better than learning to follow instructions by rote. Not to say all teaching is that way, but it seems like a majority.
Another resource is MOEMS, the Math Olympiads for Elementary and Middle Schools. They are totally reasonable and also fascinating problems. Get one of the books and check it out if you are working with someone in the late elementary.
[0] https://moems.org/