A 1 with one zero next to it means 1 multiplied by 10, or ten. A 1 with two zeros next to it means 1 x 100, or in exponents 102, or a hundred. A 1 with three zeros next to it means 1 x 1000, or 103, or a thousand. Ten is ten times bigger than one, and a hundred is ten times bigger than ten, and a thousand is ten times bigger than a hundred.
For larger numbers, the sequence goes like this:
- 10,000 = 104 = ten thousand
- 100,000 = 105 = a hundred thousand
- 1,000,000 = 106 = a million
- 10,000,000 = 107 = ten million
- 100,000,000 = 108 = a hundred million
- 1,000,000,000 = 109 = a billion
- 1,000,000,000,000 = 1012 = a trillion
- 1,000,000,000,000,000 = 1015 = a quadrillion
The biggest numbers anyone has named are a googol, which is one with a hundred zeros after it (10100) and a googolplex, which is one with a googol zeros after it (10googol). A googol is so big that it is more than the number of atoms in the universe as far as we can see with telescopes (about 1080). A googolplex would be a lot more than that - there's no real number of things that comes anywhere near a googolplex. But those aren't the biggest possible numbers, because you could always say, "a googolplex plus one, a googolplex plus two," and so on. Numbers are infinite, so you never come to the end of them.