I came home a bit early today. At one of the intermediate stations, a mother with two children got on. She and one child sat behind me and the other child, a boy of maybe 6, took the seat next to me. He basically sat with his back to me chatting to his family, but he turned round just before they got off, and he looked at my note book, covered in sketch graphs, algebra and calculus. As they got off, I heard him say "Mum, what was that man doing? It looked like maths, but with letters..." It made me smile, anyway. I had almost forgotten maths with only numbers.