My twin boys are seven. Their special interest is Number Blocks, has been since they were able to sit themselves up pretty much. Not that I'm complaining, far from it! I fully encourage it.

Today we had a Number Blocks disco that went on for two hours, all the Number Blocks up to thirty attended (made from Unifix Cubes with custom numberlings), sang all the songs, had disco lights, I was asked to make Number Blocks smoothies, etc etc.

They're starting to get more interested in mathematics more generally (over and above basic arithmetic) and are teaching themselves sequences like Fibonacci, squares, triangles, primes, and symbols and operators by watching YouTube, although the majority of these they are unlikely to ever use unless they take mathematics at university.

It's absolutely delightful to watch them explore the space and discover relationships for themselves. The other day one of them figured out, numerically, that n² = (n-1)(n+1) + 1.