# Talk:Decimal mark

## Dominican Republic

In Dominican Republic the decimal separator is a point, not a comma. The article is wrong. —Preceding unsigned comment added by 66.98.23.232 (talk) 18:57, 6 June 2009 (UTC)

## Who said Peru?

I'm Peruvian and I use a dot as radix point but this is because the school I grew in is a Brittish school. My last years in school (which I spent in another non-Brittish school), my experience in university and the standard I find in most computers customized to local taste have the comma as the radix point (with a space for the thousands). Said this I could not be someone who has studied this in the Peruvian context but adding my own experience to the oddity that Peru seems to be the point-decimal-separator-using-country among its neighbours I can guess someone has used wrong data, probably provided by exceptions similar to mine. On the other hand, I recognize the use of the dot over the comma could be growing but without a proper source I lay claim to a good reason to doubt this.Undead Herle King (talk) 02:27, 4 March 2008 (UTC)

## Comma or point?

Instead of a stub just one question. What is preferred in Wikipedia at the moment - a decimal point or a decimal comma? Or how we should write numbers here. For example: 7 thousand + 1/3: 7,000.3 or 7.000,3? [this unsigned comment was added 16:04, 4 September 2002 by XJamRastafire, and subsequently moved to the Talk page by Derek Ross]

This is an English language text so we should use 7,000.3 -- Derek Ross 22:56, 20 October 2002
That would be 7,000.3333...
Some people prefer to use a space as a thousands separator, thus: 7 000.333 33 or something like that. I have seen it in some of my textbooks (in the USA). -- User:Juuitchan [15:50, 15 September 2003 as 137.99.216.235]
There's also a dot above notation to indicate repeading digits: 7,000.3̇ (Your brower should display a dot above three.) If more than two digits repeat, then use two dots: 1 / 7 = 0.1̇42857̇. That's one way math books do it, anyway.--69.212.98.139 02:20, 13 November 2004 (UTC)
I believe SI usage for comma marking is the space (7 000 not 7,000), but I'm not sure if there's an SI standard for the decimal separator. T. S. Rice 05:53, 29 June 2006 (UTC)
I thought thin space was the SI standard. The trouble with using space here is that full width space makes things confusing (is that one big number or multiple seperate numbers) and thin space suffers from poor font support. Plugwash 02:52, 11 February 2007 (UTC)

It is true that this is English Wikipedia, but perhaps the English Wikipedia is used by the most non native speakers. using comma and point in the same number can be very confusing, but the SI standard would be useful: use space (preferably non-breaking space) as thousand separator and dot (or comma) as decimal separator.Timur lenk 19:38, 11 February 2007 (UTC)

Regarding choice of decimal separator, the definitive answer is in WP:Style#Decimal_points:
"A decimal point is used between the integral and the fractional parts of a decimal; a comma is never used in this role (6.57, not 6,57)."
Regarding choice of thousands separator for numbers greater than 9999, the definitive answer is in WP:Style#Large_numbers:
"Commas are used to break the sequence every three places (2,900,000)."
I'm going to add a Wikilink to WP:Style#Decimal_points to the main article, too, since seeking an answer to this question is probably one of the most common reasons that people come to this article, and it is not obvious where the answer is to be found. NCdave (talk) 06:58, 17 March 2008 (UTC)
BTW, WP:Style#Large_numbers also says, "Billion is understood as 109" (which is probably an even more contentious topic!) NCdave (talk) 07:10, 17 March 2008 (UTC)
South Africa uses a comma between the integral and the fractional parts of a decimal, so there is at least one national variety of English that uses the notation. It's an interesting one, because South Africa switched from the British style point to the European style comma when it switched to a decimal currency and SI units (I'm not aware of any other country that did so, as it's not an integral part of the SI). — Preceding unsigned comment added by 82.32.72.129 (talk) 10:06, 10 November 2011 (UTC)

I am reading a Peruvian geological document and am confused by the decimals and delimiters. It seems the '.' is used consistently as the radix point, but the ',' delimiter for thousand marks is very odd. For example, numbers under one million are noted like: 895.767.00. Whereas figures over one million use an apostrophe then a comma, like: 11'232,181.00. Then, to make things more confusing, the next thousand mark uses no comas and goes back to '.', like: 205'838.948.00. I do not know if this is the convention or just an aberration. — Preceding unsigned comment added by 207.216.241.78 (talk) 23:35, 7 November 2012 (UTC)

## Zimbabwe changed to dot

I would like to say that Zimbabae uses the dot after changing from the comma early this year.[this unsigned comment was added 06:51, 16 November 2004 by 202.27.216.185]

## Middle dot

I've changed the term "raised dot" to "middle dot" to facilitate a link to the article on "middle dot". However, if the term "raised" is commonly used, please add it back (and presumably see to the the article on "middle dot". Thincat 10:26, 23 Dec 2004 (UTC)

## which came first

Does no one know if the dot or the comma was first? This seems as such an important change that it would be formal somewhere and noted. Please send me an E-mail if you know. Thanks. lalli.oni@gmail.com --194.144.0.59 15:15, 7 Apr 2005 (UTC)

## Ireland?

As it seems to generally be a language thing, does anyone know if Irish uses 12,345,678.90 or 12.345.678,90 or something similar to the latter. The reason I ask is because when browsing the Irish wikipedia, I noticed on the page on euro [1] that the exchange rates into euro were given in the format 0,787564 for the Irish pound for example and was just wondering if that's the official Irish language way of doing it. I would've asked over there but my Irish isn't THAT good. - RHeodt 10:42, 17 February 2006 (UTC)

A few months after you asked this question, Picapica, whose Irish is as good as anyone's, changed all the commas to full stops. I suspect the original page was just copied over from German Wikipedia or something and no one had bothered to change them before. —Angr 08:28, 18 October 2006 (UTC)

## Arabic and Persian

Saudi Arabia, and other Arabic countries, use neither a coma nor a dot to separate the decimal part. They use a character very similar to a forward slash (/) but sort of smaller (but not yet a coma.) This also applies to Persian (Farsi) writings. I'm not sure if we should add another category for these countries or not. Also, I'm not sure what name to use for this possible category. In Arabic and Persian, the character is called "Momayyez" (double "y" showing a stress and delay when pronouncing the /y/ sound.) Please contribute your ideas. hujiTALK 18:42, 4 May 2006 (UTC)

Its been so long time and it is still not satisfying. There should be at least one small picture. I looked for Momayyez on google images, and came to the site http://fiveforks.com/ted/2007/06/commas_in_thousands/ - he writes:

That brings up one of the flaws of Wikipedia: tons of information but not always an answer. And sometimes way more information and opinion than you really want or need.

Although the Wikipedia article about the momayyez says it is a forward slash, in the article it appears as a comma. Searching for images of a momayyez on Google results in pictures of a guy with a mustache and a woman in a cubicle. I played around with the unicode character in Word and came up with this image that shows that the momayyez looks a little different and does not descend like a comma. I will reiterate that since the momayyez is a decimal separator, the first image represents 40 to three decimal places and the next one 40,000.

he further gives a picture there, but still it is unclear for me and anyone is confused in this article. After so many years, there must be some updates finally. thats really a shame Slighter82 (talk) 20:13, 18 July 2013 (UTC)

This page has horrible junky links that link to disambig pages, and some links are simply unnecessary. For example, I removed linke to part, stop, and mark. Wikipedia is not a link dump. Links should only be used to make the current topic more clear.

So please, do not just link everything and anything. And when you do link, make sure it links to the right place. Fresheneesz 21:03, 27 May 2006 (UTC)

Thanks hujiTALK 13:14, 28 May 2006 (UTC)
all links were done by a single user [2]. I've tagged the page for clean-up as he did this to a number of pages and if no one cleans it up by the time I get back I will attempt to clean it up. You can pretty much wholesale remove any links he added. --Crossmr 07:09, 18 June 2006 (UTC)

Is it really necessary to link to every country mentioned in this article? In the section "Hindu-Arabic numeral system" every country listed is linked, and the links don't go to a specific part of the article linked, i.e. number systems in the specific country, they just link to the country's Wiki page. Just linking to a country's Wiki page doesn't seem germane to the article as it adds nothing to the article's topic. Zargon2010 (talk) 10:05, 18 July 2011 (UTC)

## Editing

So, I just did a fairly long edit on this; I hope my contributions helped a bit? Hopefully I didn't mess anything up, as I took quite a few liberties in changing things. T. S. Rice 07:22, 29 June 2006 (UTC)

## Switzerland

According to the German Wikipedia [3] and also to my own experience, Switzerland is a dot and not a comma country with regard to the decimal separator in use. --217.162.63.232

I live in Switzerland, and it is definitely a comma country; ISO 31-0 imposed comma is law, and is enforced in aducation an normalization. However, dot as decimal separator filters down for monitarian use, as a result of American influence in the banking system, a powerful element in Swiss economics. -- Dutchguy 10:55, 10 February 2007 (UTC)

I want to note here that the Source linked in the Article is very bad. I would suggest that the official source gets added directly from the Swiss government site http://www.bk.admin.ch/dokumentation/sprachen/04915/05016/ — Preceding unsigned comment added by 80.218.11.205 (talk) 21:35, 24 October 2012 (UTC)

I also live in Switzerland and want to note that the source proposed here is of no use, it only gives the conventions used in the federal administration. Switzerland is a country where many people use the dot and many people use the comma; and as everything "it depends on the canton". (However, some people feel very strongly about the way they learnt it in school themselves which is why the German article currently claims Switzerland to be a "comma country".) --129.132.146.194 (talk) 12:52, 26 March 2013 (UTC)

## 1'234'567.89?

I am German, and I have never come across or heard of that style... can anyone attest for its existence? Lewis Trondheim 20:07, 13 February 2007 (UTC)

Not very likely. Both ISO and SI forbid the use of dot and comma as grouping symbols; comma is the preferred decimal separator, but because of persistant use of dot as decimal separator in most English speaking countries, neither symbol should be used for grouping to avoid confusion between grouping symbols and decimal separators. Small spaces are proposed for grouping, but (in handwriting mainly) high commas could be used. But if someone keeps to normalization by using correct grouping symbols, that person would also use a comma as decimal separator as prescribed in the first place. So, 1'234'567,89 is, also in my own experience, commonly used, but not 1'234'567.89 -- Dutchguy 21:04, 13 February 2007 (UTC)203.124.0.246 11:39, 21 February 2007 (UTC)
I've always personally used it since I was a very young child (in the UK) and I'm sure others do in English-speaking countries given the ambiguity created by using a comma alongside a decimal point, the difficulty producing handwritten thin spaces and the apostrophe's similarity to the comma. It is also common on pocket calculators in English-speaking countries.
Maybe, the fact that pocket calculators (particularly those with 7-segment displays) seem to invariably use the apostrophe as a thousands separator (if they have one at all) should be mentioned in the article. I don't have a reference. This is, I'd imagine, due to the impracticality of differentiating a comma and dot on a low-resolution screen, the impossibility of having two segments occupying the same area on a 7-digit display and the impossibility of moving thousand separating spaces to the right place in a decimal fraction with a segment-based display or other display that physically separates out characters.
Joe Llywelyn Griffith Blakesley talk contrib 03:35, 18 December 2008 (UTC)
In Switzerland also, we commonly use the apostrophe as thousand separator (1'234,5). —C.P. (talk) 15:38, 19 March 2009 (UTC)
As a Briton living in Germany, working for a European organisation, I have often had to contend with dot vs. comma problems, both for the decimal mark and the thousands separator. I was, however, surprised to find that bankers here often use the apostrophe or prime as the thousands separator, perhaps due to Swiss banking influence. Perhaps this is why many pocket calculators here nowadays also use a thousand separator. The aforementioned bankers also use the apostrophe or prime as a shorthand for three zeroes in round thousand, million, or milliard amounts, thus: 5' (five thousand), 15' (fifteen thousand), 200' (two hundred thousand), 10" (ten million), 15"' (15 thousand million or 15 milliard (not 15 billion!)). —Preceding unsigned comment added by 145.64.134.245 (talk) 10:04, 20 January 2011 (UTC)

## Arabic Decimal Separator

I am not sure if "Arabic Decimal Separator" is in fact different from a comma. It may have been customary previously to use a half-slash-like punctuation. The following are Unicode defined Arabic separators. Click on the links to see how they look like.

• Arabic Thousands Separator U+066C
• Arabic Decimal Separator U+066B

I tried setting my Window's regional setting to Saudi Arabic, all I see are the above symbols with Arabic-style numbers. I also tried setting my regional setting to Farsi, the only difference is that it uses a "/" as decimal. --Voidvector 20:58, 7 July 2007 (UTC)

## Ordered pairs

In countries where the comma is used as the decimal separator, how are ordered pairs (or n-tuples, or sets, for that matter) written when using fractional numbers? How do you distinguish {12.5, 3.7} from {12, 5, 3, 7}? Benandorsqueaks 19:55, 1 October 2007 (UTC)

I assume that there is no space between the numbers when the comma is used as a decimal separator (2,5) but there is a space when it is used to separate terms (2, 5). Comrade4·2 22:47, 15 December 2007 (UTC)
We use semicolons: {12,5; 3,7}. --Army1987 (talk) 20:28, 24 June 2008 (UTC)

"The choice of symbol for the decimal mark affects the choice of symbol for the thousands separator used in digit grouping. Consequently the latter is treated in this article as well." This is from the article. Something of the above mentioned should be fitted into the article. BTW I too use a semicolon.

About "thousands separator": it's a badly chosen designation since it makes sense in any base. Here is something I learned at maths teacher's school: Try arranging say 63 small cubes using base ten, base nine, base eight....down to base two. (I spell out i.e. nine instead of 9 since 9 doesn't exist in base nine. One of my pedagogical(?) ideas.)Soon you will have "rows", "plates" and "cubes" and over again at a sort of higher level. "rows", "plates" and "cubes" they are three, hence the grouping of three.

"Making groups of three digits also emphasizes that there is a base 1000 of the numeral system that is being used, which is not always a given (for example, in computer science)." What is this? "base 1000". In base ten you have ten digits. I would like to see the ASCII-codes for these thousand digits. No, better still, remove the sentence.

## ISO - IEC - CEN - CENELEC - ETSI: they all use the comma

Both the international (ISO, IEC) and European Standardization Organizations (CEN, CENELEC, ETSI) have standardized the use of a comma as the decimal sign and just a space interval as the thousands separator in all languages they publish their standards. Έκτωρ (talk) 19:26, 15 December 2007 (UTC)

## 1.234.567'89

Does nobody use the raised comma or the apostrophe to seperate the unit form the first decimal? --Error (talk) 02:30, 13 January 2008 (UTC)

That's correct; nobody uses it. Teemu Leisti (talk) 11:47, 30 March 2008 (UTC)

## Invented In Scotland

The teaching In Scotland website

http://www.teachinginscotland.com/tis/63.1.8.html

Seems to indicate that the decimal point originated in Scotland, as this isn't a rubbishy website and has some authority behind ti I was wondering if there should be a mention of it on here...

86.163.189.159 (talk) 03:25, 18 January 2008 (UTC)

If you can provide a more authoritative reference, inserting it shouldn't be a problem. A simple mentioning on non-history/math webpage is at best a claim. --Voidvector (talk) 17:09, 18 December 2008 (UTC)

## Numeral system

This page does not make the distinction between different numeral systems used around the world. So to talk only about dot vs comma is rather incomplete. --Voidvector (talk) 06:25, 20 June 2008 (UTC)

## HP-11C Calculator

The following comment might be appropriate somewhere: "The Hewlett-Packard HP-11C Calculator can change between using a comma and a decimal by holding down the decimal point button when turning the calculator on." I have an HP-11c calculator and it has this feature. However, I am not comfortable enough with code to make the change to the main article itself. Also, I am not sure what the best place to put this comment would be, so if someone would like to do this for me, please do. You might also add a link to the HP-11c calculator page. MarkWales (talk) 02:19, 18 October 2008 (UTC)

## Indian lacs

The article says this: "comma is used at levels of thousand, lakh and crore, for example, 10 million (1 crore) would be written as 1,00,00,000. This is repeated at thousand crore, one lakh crore and a crore crore (1,00,00,000,00,00,000). Note that the pattern of comma is groups of 3,2,2 again 3,2,2 from right side." However this is contradicted by the accompanying table which shows that apart from the last three digits the numbers are always in groups of two, e.g. 1,00,00,00,00,00,000. Which is correct? 194.75.129.200 (talk) 14:07, 14 November 2008 (UTC)

I didn't understand this part either. It was nonsensical to me.--41.238.140.187 (talk) 07:31, 22 January 2011 (UTC)

## Decimals to Fractions

0.1=1/10 0.01=1/100 0.001=1/1,000 0.0001=1/10,000 0.00001=1/100,000 0.000001=1/1,000,000 0.0000001=1/10,000,000 0.00000001=1/100,000,000 0.000000001=1/1,000,000,000 0.0000000001=1/10,000,000,000 0.00000000001=1/100,000,000,000 0.000000000001=1/1,000,000,000,000 0.0000000000001=1/10,000,000,000,000 0.00000000000001=1/100,000,000,000,000 0.000000000000000=1/1,000,000,000,000,000

...and so on.§÷×±{{{{{[[[]]]}}}}}

## Netherlands

We don't use spaces as thousands separator in the Netherlands (see here) we use the periods for thousands separator and the comma as decimal separator. If no one objects I will change this. Sitethief~talk to me~ 21:06, 22 August 2009 (UTC)

Seems like SABS M33a is the correct source for the information. I do not have a copy of the standard.....

See https://www.sabs.co.za/Business_Units/Standards_SA/WebStore/search/detail.aspx?id=4226&lang=EN MoHaG (talk) 04:31, 26 November 2009 (UTC)

I have never seen a comma used as a decimal point in South Africa and I've lived here for my entire life. The Johannesburg Stock Exchange doesn't use a comma as a decimal point, shops, banks, government institutions, etc -- NONE of them use a comma as a decimal point.

My South Africn bank statements (Absa bank) use the comma (if posted) and the full-stop (if downloaded). If you've never seen the decimal comma it simply means that you live in a publication bubble that uses only the full-stop. Many publications use the comma. The link most likely refers to "Supplement 1 of the Government Gazette R1146 of 5 July 1974". ABSA Bank (a large bank in South Africa) uses the decimal comma in their annual report [[4]]. -- 105.224.83.106 (talk) 08:03, 7 August 2014 (UTC) (leuce, not signed in)

Using a comma as a decimal point here would get you some extremely odd looks. — Preceding unsigned comment added by 41.135.110.211 (talk) 22:35, 20 August 2012 (UTC)

### Government style guide

I removed the text and link "(officially[1])" because that document is not official policy but simply the style guide for that particular government department. The document does not state anywhere that it is meant as government policy. Furthermore, the document contains many items that apply to English only, and many of the items in it are obviously recommendations but not requirements. -- 105.224.83.106 (talk) 08:03, 7 August 2014 (UTC) (leuce, not signed in)

## always common-sense exceptions?

Postal number and ID-numbers are grouped in Sweden, like this:

• 703 75 instead of 70375 for postal codes, and
• YYMMDD-XXXX for personal numbers.

Is this a reason to change the text? Moberg (talk) 14:58, 12 April 2010 (UTC)

## Decimal mark vs. Decimal point

Decimal mark? I've never heard this term in all my engineering years. Moreover,

http://www.google.com/search?client=safari&rls=en&q=%22decimal+mark%22&ie=UTF-8&oe=UTF-8 shows <9000 instances of "decimal mark"

vs.

http://www.google.com/search?num=100&hl=en&client=safari&rls=en&q=%22decimal+point%22&aq=f&aqi=&aql=&oq=&gs_rfai= which shows > 1,420,000 instances of "decimal point"

This title of this page should be fixed, and decimal mark should redirect to decimal point, instead of the other way around. This is clearly the world-wide preferred phrase. —Preceding unsigned comment added by 94.252.120.217 (talk) 11:32, 9 December 2010 (UTC)

You call it the DECIMAL POINT because you use the POINT as the decimal MARK. Other cultures use other MARKS. HkCaGu (talk) 12:36, 9 December 2010 (UTC)
Nonetheless, it's name in English is "decimal point". It's confusing the issue to call it otherwise. I agree that the comma is the mark in other languages, but that's not a reason to present a page that misleadingly implies that the correct name is "decimal mark". Maybe there's a way to make this point clearer? Even the very first text on the page seems confused: "For the proper choice of the decimal mark in English language Wikipedia articles, see Wikipedia:Manual of Style#Decimal points." —Preceding unsigned comment added by 94.252.120.217 (talk) 13:15, 9 December 2010 (UTC)

1. Have an empty article redirect from decimal point to decimal mark. 2. This is an article who's FOCUS is that typographical "thing" between the integer part and the fractional part. In some languages that "thing" is a full stop, in other languages something else. There must be no preferances from start in an encyclopedic article. How many of those > 1 420 000 instances have this focus? You can't use statistics like that. — Preceding unsigned comment added by 83.223.9.101 (talk) 12:25, 23 August 2012 (UTC)

The Bureau International des Poids et Mesures states: ...5.3.4 Formatting numbers, and the decimal marker The symbol used to separate the integral part of a number from its decimal part is called the decimal marker. Following the 22nd CGPM (2003, Resolution 10), the decimal marker “shall be either the point on the line or the comma on the line.” The decimal marker chosen should be that which is customary in the context concerned. If the number is between +1 and −1, then the decimal marker is always preceded by a zero. (−0.234, but not −.234) Following the 9th CGPM (1948, Resolution 7) and the 22nd CGPM (2003, Resolution 10), for numbers with many digits the digits may be divided into groups of three by a thin space, in order to facilitate reading. Neither dots nor commas are inserted in the spaces between groups of three. (43 279.168 29, but not 43,279.168,29) However, when there are only four digits before or after the decimal marker, it is customary not to use a space to isolate a single digit. (either 3279.1683 or 3 279.168 3) The practice of grouping digits in this way is a matter of choice; it is not always followed in certain specialized applications such as engineering drawings, financial statements, and scripts to be read by a computer. For numbers in a table, the format used should not vary within one column. — Preceding unsigned comment added by 83.223.9.101 (talk) 12:58, 27 August 2012 (UTC)

## Fraction digit grouping

This article could probably do with some additional info on the grouping of digits in the fractional part of a number. What is the prevalence of fraction grouping in various countries/cultures? It seems that, in most cases, the practice is to use no grouping. Are there places that commonly do? BigBadaboom0 (talk) 14:12, 27 January 2011 (UTC)

see International Bureau of Weights and Measures (Bureau International de Poids et Mesures) The International System of Units (SI) pdf section 5.3.4 "Formatting numbers, and the decimal marker," page 133 Zyxwv99 (talk) 13:51, 24 September 2012 (UTC)

## Which country

Could someone explain the bottom-left corner of this poster from 1905: http://upload.wikimedia.org/wikipedia/commons/a/a2/The_great_Victorina_Troupe.jpg I don't know hich country it's from (obviously an English-speaking one that used dollars in 1905), but they seem to use a period (.) to delimit the thousands and an underline for the decimals. This article does nothing to give me an indication as to where it is from.

(i.e, could someone edit the 'history' section to explain where and when this poster is from) — Preceding unsigned comment added by 132.165.76.2 (talk) 13:11, 22 December 2011 (UTC)

It's from USA. Printed by The Donaldson Litho Co. c. 1905, which you can find out in two minutes if you know how to use a search engine like, for instance, Google (how I miss AltaVista!). BTW, this is not a Q&A page. --Episcophagus (talk) 19:05, 5 November 2012 (UTC)

Similarly, in hexadecimal (base 16), full spaces are usually used to group digits into twos.

I've never seen groupings of two - always four. Windows Calculator uses four when digit grouping is enabled. Simple fix is to change "twos" to "twos or fours" but I'm curious if anybody actually uses two digits?

Poster Nutbag (talk) 14:37, 14 February 2012 (UTC)

## History section

What the heck is a "units digit" as mentioned in the history section? It's linkified to point at the digit page, which is of no help. Without a specific definition this passage doesn't make any sense. Monolith2 (talk) 16:24, 4 September 2012 (UTC)

The ones place, as opposed to the tens, hundreds, tenths, etc. — kwami (talk) 02:18, 5 September 2012 (UTC)
It's like the "unit block" referred to in police and fire department reports. If you live at 14 Maple Street, you don't live on the 200 block or the 100 block, you live on the unit block. Zyxwv99 (talk) 13:54, 24 September 2012 (UTC)
Consider the number 16,735.2809; the five is the units digit, the three is the tens digit, the seven is the hundreds digit, the two is the tenths digit, etc. P.S. talk of 100 block, 200 block, etc. won't make sense to those unfamiliar with North American addresses. In Australia, for example, the lots are numbered consecutively (without skipping numbers) ... it's less convenient. JIMp talk·cont 01:28, 10 October 2012 (UTC)

## Pythagorean arc?

This article says: "Gerbert of Aurillac marked triples of columns with an arc (called a "Pythagorean arc")". However, according to History of Mathematics, Volume 2, p. 177 by David E. Smith a "Pythagorean arc" is the same as the abacus itself. --Episcophagus (talk) 18:53, 5 November 2012 (UTC)

## Recommended character for thousands separator?

There seems to be consensus about separating thousands with a small space, but what does it mean precisely in terms of Unicode character? I haven’t found official recommendation about this.

• The page Space (punctuation) says that the Unicode Thin Space is “[r]ecommended for use as a thousands separator for measures made with SI units. Unlike U+2002 to U+2008, its width may get adjusted in typesetting.[24]”, with the ref pointing out to “The Unicode Standard 5.0, printed edition, p.205”. It is available here, if I am not mistaken. This document does not mention thousands separators, thus the reference only covers the “adjustable width” part of the quote here above. This leaves the first claim, that Unicode Thin Space is recommended for use as a thousands separator, without source. I do not think that the Unicode Thin Space would be recommended for use as a thousands separator by anybody (or by any serious body), because it is breakable.
• If one insists on separating thousands with Unicode Thin Space, then it should probably be complemented with a Unicode Word joiner (“The word joiner can be used to prevent line breaking with other characters that do not have nonbreaking variants, such as U+2009 thin space or U+2015 horizontal bar, by bracketing the character.”, section 16.2, p. 534, Unicode Standard 5.0). But this seems far-fetched, and just my idea, there is no evidence (that I found) that it is recommended by any official body.
• According to the wikipedia page about ISO 31-0, “small space” is recommended for thousands separation. It may be that ISO 80000-1:2009 talks about this (because it supersedes ISO 31-0), but I do not have access to it. Can someone check in there if anything more precise is specified?
• The International Bureau of Weights and Measures (referenced in Decimal_mark#Digit_grouping) indicates the following. “Following the 9th CGPM (1948, Resolution 7) and the 22nd CGPM (2003, Resolution 10), for numbers with many digits the digits may be divided into groups of three by a thin space, in order to facilitate reading. Neither dots nor commas are inserted in the spaces between groups of three.” There is no indication that the phrase “thin space” there refers to a Unicode Thin Space, it should probably be understood non technically, as a space that is not large but thin. Also, Resolutions 7 and 10 do not use the wording “thin space”.

It would be good to find some official recommendation about which character to use as a thousands separator. I can only think of Unicode Narrow No-Break Space as a proper separator for thousands. But maybe there are other opinions out there.--OlivierMiR (talk) 12:51, 13 May 2013 (UTC)

Note that this question is related to, but different than, the question of separating numbers and units, see Talk:Space_(punctuation)#Reference_for_thin_space_between_numerals_and_units.--OlivierMiR (talk) 13:04, 13 May 2013 (UTC)

## Decimal mark without the integer part?

What about the American (?) custom of writing "0.5" as ".5", that is "a symbol used to separate the integer part nothing from the fractional part of a number"? It looks quite weird for people from Europe, so maybe somebody can write a referenced summary about such use, its history and what various standards/style manuals think about it? — Mikhail Ryazanov (talk) 00:31, 22 June 2013 (UTC)

The omission of the leading zero from decimal numbers less than 1.0 has several contexts of appearance. The widest context is in unedited usage in which people (almost anyone, not just Americans) are simply not being fastidious about typing the leading zero. But another context of usage, for which there are plenty of references available, occurs also in edited and published usage, which is in statistics when talking about quantities that can never be more than 1.0, such as α, β, and P. Various house styles drop the leading zeros on such values, including AMA style and APA style. I don't agree that either of the above contexts (the carefree unedited one or the edited statistical one) are unfamiliar to Europeans in any generalized, stereotyped way. As for AMA and APA style being American, well, there is a global STM audience that encounters them on a daily basis. They may simply be unfamiliar to some individual Europeans. Quercus solaris (talk) 02:09, 29 July 2013 (UTC)

## Country/language

This article talks about countries instead of languages. Even though in many countries there might be an "official" decimal mark (and this will be given by law), in many cases the authorities of the language (and not a government) determine what should be used. Then, it makes no sense to say that in Spain the style "1.234.567,89" is older. According to the reference (RAE), this happens in Spanish (everywhere in the world), and this does not necessarily happen in Spain in any of the other official languages. Another example: French/English Canada. In many cases, the writing depends on the language, not the country (should I write 1˙234˙567,89 if I write in English but I am in Italy?). — Preceding unsigned comment added by 88.17.128.16 (talk) 13:33, 16 March 2014 (UTC)

## Digit grouping

This section of the article claims that in countries (basically the Chinese culturosphere) which have numerals which go up in 10000s, the separator divides groups of four digits. Although this would be obviously the rational way to do it, at least in Japan this claim is totally false. It is essentially never done (with the possible exception of rational foreigners); the commas are put every three digits, and people perform these amazing power conversions in their heads, to read for example 100,000,000 as 'ichi-oku' (i.e. one ... 10^8) You will even see large amounts of money written in units of, say 10万 (10...10^4 : i.e. 10^5), and the numbers will be written as 12,340, (i.e. 12 340 00000 = 1 234 000 000), leaving the comma before 10^(3+5)). If someone can confirm practice in Korean or Chinese, we can probably replace this. Imaginatorium (talk) 10:03, 3 July 2014 (UTC)

Just a followup: Chinese WP, via Google translate because my knowledge of Chinese is very restricted (though nonzero), in Chinese the separation by four digits is *sometimes* done. Imaginatorium (talk) 10:12, 3 July 2014 (UTC)

## Are alternating thousands separators for real? And is a book from 1923 a source in this internet age?

Someone added into the text: "The sorce (sic) [19] is a book from 1923 - so reliable to (sic) the internet age? Never seen in real life that one uses 1.234,567.890,12."

(a) There are discussions about texts from 1905 above. 1923 is well within the time where lots of texts survive up to now - please finde the respective fields yourself.

(b) The book's reliability does not change with the "internet age". The number is written as it is.

(c) I have learned this way of digit separation in school in the 1970s. However, this is not a valid citation for WP, so I looked for some real use. I did not do an extensive scientific search for newer documentation, e.g. school books - but take it for granted that it was used like this much longer than 1923. If you look into the article, you will see many more claims that are not at all supported by any evidence.

(d) "Never seen in real life that one uses ...". I am happy to learn about all the German and Austrian texts you have read, and the authors of books with such numbers you had personal contact with to claim that your "(I've) never seen ... that one uses ..." is a relevant portion of German and Austrian writing culture. Please cite the research you did that shows that my addition (of a factual use of signs) is, at some relevant time, never used.

Cheers.

--haraldmmueller 19:54, 9 September 2014 (UTC) — Preceding unsigned comment added by Haraldmmueller (talkcontribs)

1. ^ GCIS (2011). Editorial Style Guide. Pretoria: Government Communications & Information System. p. 24. Retrieved 2013-02-13.