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Writing Commas in Numbers

```Date: 07/11/2003 at 15:17:35
From: Megan
Subject: France's Math System

Is it true that in France where we in America use decimals in math,
they use commas, and where we use commas they use decimals?  An
example would be we would write 3,998.60 and they would instead write
3.998,60.
```

```
Date: 07/11/2003 at 17:09:38
From: Doctor Peterson
Subject: Re: France's Math System

Hi, Megan.

Yes, this is true of much of the non-English-speaking world.

I have long wanted to find a good reference that would show me where
each convention is used; one that you might find interesting is the
Regional and Languages Options box in Windows XP (other versions of
Windows may do it differently), where you can select from a long list
of countries and see the default choices they give for writing
numbers, currency, times, and dates. I don't know whether I always
trust Microsoft to know the correct way to use any language, but the
variety of options is fascinating! Try picking any European or South
American country.

Here are some references I have found that tell a little more about
it:

Commas in Numbers - Grammar Slammer, English Plus
http://englishplus.com/grammar/00000087.htm

Many European countries use a comma in place of the decimal point
and use periods or blank spaces to separate every third digit.
United States: 2,367.48 francs
France: 2.367,48 francs or 2 367,48 francs

Cross Cultural Comparisons: Numbers

France: The decimal point is a comma, as in all of Europe.
Certainly not a dot, except on computers.

How Many: Using Numbers and Units - Russ Rowlett
http://www.unc.edu/~rowlett/units/numbers.html

In English-speaking countries, the decimal point (decimal marker)
is the period. In continental Europe and most other places, the
decimal marker is the comma. ... Since the comma often means a
decimal point, the International System (SI) requires that large
numbers, like the billions above, be represented as groups of
three digits separated by narrow spaces, not by commas.

Country-Specific Data Formats
http://w3.pppl.gov/misc/motif/MotifStyleGuide/en_US/Country-
Specific_Data_Formats.html

Thousands Separators
The comma, period, space, and apostrophe are examples of valid
separators for units of thousands as shown in the following
examples:

1 234 567
1.234.567
1'234'567
1,234,567

Decimal Separators
The period, comma, and the center dot are examples of valid
separators for decimal fractions as shown in the following
examples:

5,324
5.324
5 324 [the dot is invisible here]

Incidentally, in some countries (such as in India) digits are not even
grouped in threes as we do, because they have different traditional
names in their languages from our "thousand" and "million." They call
1,00,000 a lakh and 1,00,00,000 a crore.

So the way we write numbers is not at all standard around the world.

If you have any further questions, feel free to write back.

- Doctor Peterson, The Math Forum
http://mathforum.org/dr.math/
```
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