Tim Richardson

 I told Xavier (5) about infinity a couple of weeks ago. He fell in love with the concept ... he knows that old people, like Grandad, walk slowly. "Daddy, if you're infinity years old, how slow do you walk?" and while brushing teeth "Daddy, I want infinity teeth".

So while going to bed, I thought I'd try to get him to understand it a bit better. What's zero + 1? 1. What's 10+ 1? 11. What's a hundred plus 1? 101 What's a thousand plus 1? 1001. What's a million plus 1? A million and one. Now watch out Xav, the next one's a trick: what's infinity plus 1? Infinity. I was impressed and surprised, I have to admit.  How did he know the answer, I asked. "Well, infinity is the last number daddy". Not a bad definition.