Date: Tue, 5 Aug 1997 22:13:18 -0400

From: Alex Bogomolny

A comma comes after every three digits counting from the right:

five billion | 5,000,000,000 |

three million | 3,000,000 |

two hundres thiry-six thousand | 236,000 |

eight hundred fifteen | 815 |

Note that usage of the word billion in the US (above) differs from that in Europe. Europeans would call the number above five milliard whereas five billion in their view requires 12 zeros: 5,000,000,000,000.