Children ask the most difficult questions. So, it is important that they don't get lost. I have this belief: If you can break down a difficult concept into stuff that the child can relate to, then many of the concepts that are acknowledged as too difficult for a young child ("it is too early for him to know"), can be made not only understandable but enjoyable. And the child learns it in a way that they will never forget.
When my child was in Kindergarten, he asked one day:
Mum, What is the biggest number?
Me: What is the biggest number you can think of?
He: A million?
Me: And what happens when you have a million lollies? J
He: Wow, can I? J
Me: Ok, so, imagine, just like Charlie and Mr. Wonka, that you have a million lollies.
He: Well, that would take YEARS to eat J
Me: Ok, what happens when I give you just 1 more lolly after the million? How many do you have?
He: I have a million and one lollies J
Me: So, you said 1 million is the biggest, but now you have 1 million and 1, which is bigger!
He: Oooooh, yes…so if you give me 1 more lolly I will have a million and 2, which is even bigger?
Me: Yes, you are getting it!!
He: So, if I have 2 million lollies, and you give me 1 more, that is bigger than 2 million?
Me: Yes! So, no matter how many lollies I give you, you can always add 1 more lolly to make a bigger number of lollies J
He: SO, there is no biggest number, because there is always 1 more than the biggest?
Me: Yes, and that is why the word we use to describe this is called “Infinite”. We say there are infinite numbers, because they go on and on and on and on…no matter where you stop, you take one more and one more from there, and so on.
He: So, the biggest number is called infinite?
Me: no, there is no number with the name “Infinite”. Infinite means this idea that the numbers go on forever. And the way we write it in math is we take the number 8 and ask it to lie down, like this (at this point, I write an 8, followed by a lying down 8, the sign for infinity).
He: Can I try it?
Me: Yes, sure (and he draws for a while). And by the way, going from lollies to stars, how many stars do you think there are in the universe?
He: Ooh, got it J So, that is why my book said the universe and stars and galaxies and all that stuff is infinite, because it too goes on forever?
Me: well yes, maybe yes J
He: Ooh this is mind boggling (he has learnt this new word, so he uses it liberally).
And yes, this was not a one-off conversation. We continue to explore other such pictures of infinity in the universe. He is in Year 1 now, and he has realized that infinity can go the other way too, meaning you can make a number as small as possible, by going the other way (negative numbers)!