III.

The Hierarchy of Numbers

The hierarchy of numbers is the following: million, billion, trillion, quadrillion, quintillion, sextillion, septillion, octillion, nonillion, decillion, undecillion, duodecillion, tredecillion, quatuordecillion (also spelled quattuordecillion), quindecillion, sexdecillion, septendecillion, octodecillion, novemdecillion, vigintillion.

In the French and American system of notation, each number after a million is a thousand times the preceding number; in the English and German system, each number is a million times the preceding. A vigintillion is written as a 1 followed by 63 zeros in the French and American system; by 120 zeros in England and Germany.

Decimals are written in the form 1.23 in the United States, 1·23 in the United Kingdom, and 1,23 in continental Europe. In standard scientific notation, a number such as 0.000000123 is written as 1.23x10^-7.