Marcel has always been good at maths, in the top group at school since his first year in primary, he is about a year and a half ahead of what is expected of him at 9, on the same textbook as a couple of kids further down the street who are 12.
Anyway, tonight in the car Charlotte was muttering away to herself. When I strained to hear what she was saying I realized she was doing mental arithmetic - calculating the total price of items she had seen in a shop. She didn't have a pen and paper but was simply adding up large sums orally. As I listened, it suddenly occurred to me that not only was she doing it carrying over numbers and the likes in her head but she was doing it logically, as any (English-speaking) adult would - that is to say if she was adding £3-27 and £4-42, she didn't add 27 and 42 but instead added 20 and 40 then 7 and 2. I asked who had taught her to add that way and she just looked at me and said - 'no one but it is just obviously easier that way!' So when I got to the house I was determined to try out an experiment. I took out Marcel's maths homework and gave it to Charlotte (who is 3 years behind him at school and only 6) And as I suspected, she managed it.