Kirk W. Helland, age 7, of San Francisco, California, for his question:

What is the biggest number of all?

It would take you two weeks to count to a million, with no time to eat or sleep. But you can write down a million with the figure one and six zeroes. One trillion has 12 zeros and one septillion has 24 zeros. A googol has 100 zeros. But even the monster googol is not the biggest of all numbers.

We do not know who invented the biggest number. But he must have been very wise. He loved to find miracles. When he found one, of course, it was too hard for him to understand. But it was a wondrous thing to enjoy and admire. He found a tiny mouse and lots of other miniature miracles. He found a redwood tree and lots of other miracles. Someone asked him how many miracles, large and small, there were to admire. Ah, said the wise man, there is no number big enough to count them all.

So right then We invented a new number, a number so big that no other number could touch it. If, he said, a person looks around, he can find a myriad of miracles, large and  small. A myriad, he added helpfully, is so big that nobody could count that far. Nobody even could write it down in figures. A myriad is so big that it is a numberless number. Certainly it sounds right, for a numberless myriad itself must be rather a miracle.

But there were some stuffy people who did not care for miracles. A myriad, they said, must be a number we can write. They agreed that it must be the number ten thousand. They wrote it down this way, 10,000    with a one and four zeros. Someone counted to this t,uttoncd down myriad in a day, with time out for a snack and a nap. But sensible people kept the original myriad. They knew that sometimes we need a numberless number that is too big, much too big to be counted.

These sensible people had a whole lot of other big numbers for sensible counting jobs. They wrote a thousand this way    1,000. They counted 1,000 twinkling stars in the sky, one by one, and then 1,000 more. They used 1,000 thousands to make a million and wrote it with six zeros this way    1,000,000. The million was useful for counting atoms that are too small for our eyes to see. Each atom is like a bitsy solar system and it takes about 100 million of these miniature miracles to measure one inch.

As numbers grow bigger, their tails of zeros grow longer. A billion has nine zeros. A trillion has 12 zeros. Our world is the home of more than three billion people. It is 93 million miles from the starry sun and the distance to the next nearest star is about 27 trillion miles. A quintillion is a grand number for counting drops in the oceans. It has 18 zeros and a sextillion has three more, which is 21. The weight of the world with all its miracles, large and small, is six sextillion and 570 quintillion tons. The googol is a newly invented number and so far no one has found much use for it. It has a tail of 100 zeros, no more and no less. But our miraculous myriad may have as many zeros as we choose to imagine.

There is a trick to writing the tail of zeros after a gigantic number. Start with the last zero, count three zeros and put a comma. Keep on counting to the left and put a comma after each group of three. A thousand looks like this    1,000    and a billion like this    1,000,000,000. The commas give you a quick way to figure a big number in threes. Six groups of three are 18 zeros and, snap, you have another "illion" number. This one is a quintillion.