David Hogan, age 9, of St. Catherines, Ontario, Canada, for his question:

Do numbers ever stop?

No, they don't. If they wanted to, the numbers could go on forever, getting bigger and bigger. But there is a problem here. Nobody in the world could count this far. Nobody can even think about the biggest of big numbers arid these numbers have no names. As you know, we count big numbers in tens and keep adding zeros that look like Os. One hundred has two zeros because it is ten times more than ten. One thousand has three zeros because it is ten times more than a hundred. A trillion is figure one with 12 zeros and a quadrillion has 18 zeros.

We can go on up to a decillion, which has 33 zeros. And someone invented an enormous number called the googol. It is figure one with 100 zeros. After the googol was invented, somebody invented the googolplex    which has more zeros than you want to count. Googols and googolplexes are so huge that almost nobody can cope with them.

But if you want to invent some even bigger numbers, just for fun, it can be done.