Ms Pope cautioned against limiting the enriched curriculum to the ablest pupils: "There is quite a lot of evidence that no matter who your learners are, they all need challenges. All children will be more engaged if they manage to complete a task they didn't think they were capable of."
Challenges are fun and can see if you understand maths by applying it. I think the Nrich maths puzzles are a bit like that. (Oops, crossed posts a bit).
I still argue that there is a difference between able children being taught more quickly to achieve certain test standards, and those who have a natural and thorough understanding of maths. I've got one of each and there is a difference.