Talk:Decimal separator

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)

Adding to this, the map of usage shows Peru as mixed, but the text states Peru is a comma using country. Like the writer above I can't say which is correct; the contradiction should be addressed one way or the other. Joe Avins (talk) 14:24, 16 December 2021 (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)

The ISO standard is for either a dot or a comma on the line as the decimal separator, the thousand separator is always a thin space (written as "thin space") in markup language. Avi8tor (talk) 12:46, 3 March 2023 (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)

The article currently states "ISO-8601 also stipulates normative notation based on SI conventions, adding that the comma is preferred over the full stop", from the 2000 version of the standard. More recent versions reference ISO-80000-1. The 2013 version of this standard states "The decimal sign is either a comma or a point on the line. The same decimal sign should be used consistently within a document." The resolution referenced in the standard is "The decimal marker shall be either a point on the line or a comma on the line." from 2003, adding that "In practice, the choice between these alternatives depends on customary use in the language concerned." Neither is described as being preferred. 188.39.244.66 (talk) 11:01, 21 May 2019 (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)

I've heard that Bulgaria at one time used the full stop for the decimal mark, and then changed to the comma. The change was possibly inspired either by standardization/harmonization or by increasing trade links to German. No, I don't have a reference for this. (a bit similar to the cases where certain continental Euro countries drove on the left, and had to convert as car travel became more common). Feldercarb (talk) 15:48, 24 April 2015 (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. - ^R_H^e_o^d_t 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. huji—TALK 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)

Junky links

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 huji—TALK 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)

Recently, the C programming language added support for this (C23), see N2626 - Digit Separators. This seems to be for consistency with C++ (C++14). The placement of such apostrophes has no meaning. Since C has been very influential, I expect to see this promulgate to other languages. — Preceding unsigned comment added by 2406:3400:41B:89B0:B8F6:285B:CB15:DC51 (talk) 05:51, 21 July 2023 (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). Comrade^4·2 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)

Information about South Africa

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)

That link is quite dead.

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)

This: https://www.sadev.co.za/content/how-correctly-format-currency-south-africa has reference to the comma as the decimal point in South Africa. Avi8tor (talk) 16:13, 8 January 2023 (UTC)

The South African government editorial style guide at: https://www.gcis.gov.za/sites/default/files/docs/resourcecentre/guidelines/Editorial_Style_Guide.pdf states:

• Write decimal and negative numbers as numerals: 3,3 and -4. Use the decimal comma*, not the decimal point: 17,4

million.

• When South Africa adopted the metric system, it also adopted the comma as its decimal mark. However, be

alert to the fact that many other countries, use the decimal point.

• Use a space, not commas, to indicate thousands: 3 000; 20 000. Avi8tor (talk) 16:40, 8 January 2023 (UTC)

Government style guide

I removed the text and link "(officially)" 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)

References

I restored the style guide reference together with a more recent reference from a different source, using the annotation "(uses both marks)" (in both sections) instead of "(officially)" (only decimal comma). — RFST (talk) 06:21, 4 February 2018 (UTC)

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)

Similarly, the article states that the phrase "decimal dot" is a common informal term. Is this in the UK? As an American I have never heard anything other than "decimal point" in any context. Wschart (talk) 14:34, 23 November 2015 (UTC)

No, it's not common in the UK, though I suppose it might be explained as a "dot" to a young child learning how to write money. The correct term taught to all school children following the National Curriculum is "decimal point"[5] Dbfirs 20:58, 23 November 2015 (UTC)

Decimal separator vs. mark(er)/sign (forget dot/comma/point/symbol)

Obviously "decimal point" would be inappropriate as the title of this article, but I am wondering why it was not called "decimal sign" instead of "decimal mark"? — RFST (talk) 06:29, 2 January 2018 (UTC)

"Decimal sign" appears to be the older phrase, eg this book from 1862. By way of wikipedia article name popularity, the good ol' ASCII table lists only three marks: Exclamation mark !, Quotation mark ", Question mark ?, versus nine signs: Number sign #, Dollar sign $, Percent sign %, Plus sign +, Less-than sign <, Equals sign =, Greater-than sign >, At sign @, Not sign ¬. Batternut (talk) 22:43, 2 January 2018 (UTC)

That would seem to favour "sign" over "mark", except for a fan of switching things around just for the heck of it. My specific concern was "decimal point" for C/C++ locale information (probably named in the U.S.A.) vs. "decimal sign" in ISO 8601, until I found myself redirected to "decimal mark" in Wikipedia, something I don't recall seeing or hearing before. — RFST (talk) 11:38, 7 January 2018 (UTC)

"Decimal point" is always the term in the UK, so I'd never heard the term "decimal mark" before. Reconsidering the above list of marks and signs though, most of them relate to specific representations. By analogy to the generic article currency symbol though, perhaps "decimal symbol" would be the best generic term. Batternut (talk) 13:53, 7 January 2018 (UTC)

"Decimal symbol" does not seem appropriate because the glyph doesn't really represent something. Unicode seems like a good reference, and searching with Google for domain unicode.org yielded: 1 result for "decimal mark" (but only because the given name Mark occurred after "decimal"...), 2 results for "decimal marker", 3 results for "decimal comma" (all about using a comma character), a disappointing 4 results for "decimal sign", 6 results for "decimal symbol" (some duplicates there), 8 results for "decimal dot" (mostly "raised decimal dot"), a disappointing but understandable 196 results for "decimal point" (obvious English bias), and 387 results for "decimal separator" (including "DECIMAL SEPARATOR KEY SYMBOL", already mentioned in the article). Because of this I now amend my proposal to rename the article to "Decimal separator", with a brief section discussing the other names also used, and without choosing sides between the monosyllabic words "mark" and "sign" that people would probably prefer in everyday usage (here reluctantly listed alphabetically). — RFST (talk) 05:46, 9 January 2018 (UTC)

"Decimal separator" seems to be a good option, yes. Batternut (talk) 10:03, 9 January 2018 (UTC)

I made this a new section because renaming seems kind of important, and looked at some more statistics on iso.org (even though this ignores the protected texts of the standards themselves): 0 for "dot", 4 for "marker", 6 for "mark"/"symbol", 9 for "comma", 37 for "sign", 72 for "separator", 135 for "point". My interpretation is that, with "decimal point" disqualified for bias, "decimal mark" clearly has insufficient prominence to remain the title of this article (even less than "decimal comma"!), and that "decimal separator" again has higher adoption than "decimal sign". — RFST (talk) 04:16, 10 January 2018 (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)

NIST has this to say in its' guide to the SI-system: "10.5.2 Decimal sign or marker The recommended decimal sign or marker for use in the United States is the dot on the line [3, 6]. For numbers less than one, a zero is written before the decimal marker. For example, 0.25 s is the correct form, not .25 s.

10.5.3 Grouping digits Because the comma is widely used as the decimal marker outside the United States, it should not be used to separate digits into groups of three. Instead, digits should be separated into groups of three, counting from the decimal marker towards the left and right, by the use of a thin, fixed space. However, this practice is not usually followed for numbers having only four digits on either side of the decimal marker except when uniformity in a table is desired.

Examples: 76 483 522 but not:76,483,522 43 279.168 29 but not:43,279.168 29 8012 or 8 012 but not:8,012 0.491 722 3 is highly preferred to:0.4917223 0.5947 or 0.594 7 but not:0.59 47 8012.5947 or 8 012.594 7 but not:8 012.5947 or 8012.594 7

Note:The practice of using a space to group digits is not usually followed in certain specialized applications, such as engineering drawings and financial statements." — Preceding unsigned comment added by 83.223.9.101 (talk) 12:10, 19 October 2015 (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)

Hexadecimal

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)

As a programmer, I'd say grouping is twos (if grouping at all) is most common. This is probably because two hex digits corresponds to 1 byte (8 bits). You'd use fours if the natural way to group is pairs of bytes. This is not common since numbers (signed or unsigned) are more usually stored in more than two bytes in most modern programming languages (for example Java and the JVM have 4-byte 'integer' or 8-byte 'long'; there's also a 2-byte 'short' but this is less used; .NET has similar types.). Some file formats and wire protocols use numbers in the range 0-65535 (i.e. an unsigned two byte number, hence 4 hex digits). But when describing these you are more likely to group irregularly to show the meaning of various blocks of bytes (an example: https://en.wikipedia.org/wiki/PDB_%28Palm_OS%29). One of the more common exceptions, that would group 4 hex digits (2 bytes), would be representing Unicode (in particular UTF-16) as hex. 86.140.81.184 (talk) 09:55, 15 December 2015 (UTC)

This is undoubtedly a matter of calculator vis-à-vis computer convention for which provenance is needed. kencf0618 (talk) 17:27, 15 September 2022 (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)

I concur. I agree that although there is consensus about using a small/narrow/thin space, there seems to be little or no instruction on which Unicode code point to use for it. But I feel that it makes sense and is only natural that it happened this way, at least so far, because the glyph-vs-character distinction is at work here. The cited standards are actually all talking about the glyph that they want, not about character encoding, although this fact is implicit rather than explicit (and many of their authors would not have known how to say it in those words). All that the content people (authors, readers) truly care about is the end result, namely, the glyph appearance, the line-break logic, and how much it costs to get it (as opposed to what mechanism accomplishes those); the question of what digital typography to use under the hood to achieve that end result, namely, which character encoding to use, is up to the person responsible for the encoding, whether it be a typesetter/compositor, desktop publisher, webmaster, or other "technical person". This only makes sense when you think about the fact that typesetting has changed so much over the past 4 decades. In 1974 they would have been talking about the best way to set it in hot metal on a Linotype machine; in 1984 they would have been talking about how best to achieve it in photocomposition on film; in 1994 they would have been griping about the limitations of ASCII and ISO/IEC 8859; only today do we have the luxury of bringing Unicode into the discussion and expecting it to apply widely across print and web. So it only makes sense that, for example, the AMA Manual of Style says "thin space" but doesn't mention encoding or code points. It was written by non-typesetters who expected the typesetting to be left to "the technical people", which was just as well, because the means to the end kept changing repeatedly with evolving technology. But certainly it seems plausible that maybe we've arrived now at a mature architecture that will be around for decades (Unicode encoding of digital documents), so maybe future editions of major style guides will mention particular Unicode points that they want to convene upon for particular semantic uses. I agree with you that Unicode Narrow No-Break Space (U+202F) seems like the better option for a digit-grouping character (thousands separator) than the Unicode Thin Space (U+2009) because it looks similar but is nonbreaking. But it would take someone with greater character encoding and web development expertise than I to know for sure whether there is any reason to avoid using either of these characters. One last thought that is interesting and relevant. In pre-Web professional publishing, back when people were willing to pay for human typesetters to crawl over the column of text and tweak the line breaks into aesthetic nicety, it wouldn't have mattered very much whether the breaking or nonbreaking character was used. But of course people realized that rightfully, that logic should and could be automated, and eventually there comes the era when "no business firm can afford to pay for the non-automated method anymore." Quercus solaris (talk) 22:24, 30 July 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)

"In many cases, the writing depends on the language, not the country" - but in many cases, the writing depends on the country in addition to the language (i.e., the language alone is not sufficient to know the decimal mark style). So it is useful to group by country, and for multi-lingual countries to then fork by language. The reason why the country is important (Swiss, Austrian and German decimal notation for German texts differ significantly!) is that the main "trend-setters" for notation - namely norms and school books - are usually local to countries, and not languages.

However, there is certainly no structure for this article that is simple and satisfying for all cases.

--haraldmmueller 15:23, 10 November 2014 (UTC) — Preceding unsigned comment added by Haraldmmueller (talk • contribs)

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)

• I modified that part. As far as I know 4-digit grouping is not that common in China. To convince myself I just browsed through a several Chinese wikipedia pages that contain large numbers and digits are grouped by 3. But we could definitely use an input on that. Now I know for a fact that 4-digit grouping is never done in South Korea (and presumably North) and although there have been suggestions that 4-digit grouping would make sense, that is only speaking in theory. Now since I cannot find a suitable source for East Asian countries maybe I should remove it, but I thought the info that those languages count by myriads is useful and since this page has been spreading misinformation for some time I just changed the sentence to the opposite. If people can find a good citation they can remove that tag, alternatively if they choose to remove the whole sentence I am OK with that. PS: on the kanji separator comment above, similar stuff happens in Korea as well, but I do not see them as grouping characters. It is just another way of writing: the equivalent of "thirty-seven million and five hundred twelve thousand fifty" as "37 million 512 thousand 50" it does not happen in English, but it does in those languages. IdentityCrisis (talk) 20:53, 20 October 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 (talk • contribs)

Raised dot for decimal point

I grew up in England (1950s-60s) and knew only the raised dot for decimals. As I recall, bank statements were computer printed using a raised dot (which in those day meant a systems programming operation!) into the 1970s or 80s. My guess is that this is the traditional system for the non-US English speaking world, but not anywhere else. So I have removed Japan from the list, and someone should check Korea, which sounds suspicious. The only other consideration is that I believe it is possible in vertical writing, to write decimal numbers using kanji, and then the decimal mark would be a central dot (but this is not the same as the raised decimal point). Perhaps vertical writing could/should be added as images, as I doubt if en:WP has the facility for vertical text. Imaginatorium (talk) 08:54, 3 November 2014 (UTC)

Yes, the Interpunct (centred dot) was standard in the UK until 1968 except on typewriters. Dbfirs 21:09, 23 November 2015 (UTC)

This is a misreading of the cited reference from 1968. It says that a decision was made between the decimal point and the decimal comma, and the decimal point was chosen. At the time everybody would have understood the decimal point to mean the middle dot. — Preceding unsigned comment added by 91.110.51.189 (talk) 12:25, 21 May 2023 (UTC)

Credit cards and postal tracking numbers

These appear to be using groupings of 4 decimal digits, with no obvious special significance to the groups. — Preceding unsigned comment added by 38.122.49.58 (talk) 17:32, 10 November 2014 (UTC)

Yes, but these are not representations of numbers (in the mathematical sense); they are simply strings of numerals. I do not think even mention of this is relevant at all to "decimal point (mark)". Imaginatorium (talk) 03:13, 11 November 2014 (UTC)

Spain decimal mark separator in handwriting

I am spanish, and I can give some information about that "(In Spain, in handwriting it is also common to use an upper comma: 1.234.567'89)[citation needed]" I prefer to share it here instead of editing the article.

I am Physics and Chemistry teacher, and sometimes I have teached mathematics, and despite I don't do it, I can confirm a lot of mathematics teachers do it in blackboard, they say it is more clear to write/explain range between numbers. For example they prefer (4'5 , 6,7) instead of (4,5 ; 6,7)

The RAE (Real Academia Española = Spanish (Language) Royal Academy) says it is not correct, so it somehow admits it happens. Article about "comma"

http://lema.rae.es/dpd/srv/search?id=V1EqcYbX4D61AWBBrd#4

"4. Usos no lingüísticos En las expresiones numéricas escritas con cifras, la normativa internacional establece el uso de la coma para separar la parte entera de la parte decimal. La coma debe escribirse en la parte inferior del renglón, nunca en la parte superior: π = 3,1416. Pero también se acepta el uso anglosajón del punto, normal en algunos países hispanoamericanos (→ punto, 4.4): π = 3.1416."

English translation: "Non linguistic uses: In the numerical expressions written in figures, international regulations require use of the comma to separate the integer part of the decimal part. The comma should be written at the bottom of the line, *never on top*: π = 3.1416. But the Anglo-Saxon point using normal in some Latin American countries (→ point 4.4) is also accepted. Π = 3.1416 "

It is something common in handwriting (blackboard), not very common in books / documents, so it is hard to give a reference. Just as some kind of official citation, I can give some official documents examples where upper comma is also used: chemistry exams for university access http://www.juntadeandalucia.es/innovacioncienciayempresa/sguit/paginas/distrito/examenes_sel_m25/selectividad_2011/sel_2011_quimica.zip

Enrique.garciasimon (talk) 00:29, 12 January 2015 (UTC)

Congrats on writing such a convoluted article

Most people would simply like to know the correct modern notation to use. This is not summarised in the intro, not is it ever clearly spelled out in the article. I was trying to discover the correct British notation but after reading the lengthy paragraph on this subject the article failed to ever tell me what the correct notation actually is.

Regarding the decimal mark, the answer on British style is already there. It's at Countries using Arabic numerals with decimal point > [Alpha list] > United Kingdom. Regarding the word "correct", all of the options discussed (for both decimal mark and digit grouping) are correct; which one is normative depends on language, region, and (for digit grouping) style guide. Regarding digit grouping, the article could use more clarity because the topic itself could use the same. It is not standardized by either language=English or country=UK. There are only prevailing styles to choose from, and you have to decide whose style you'll follow. For the UK, the prevailing style for digit grouping (according to both New Hart's Rules and Butcher's Copy-editing, which are two of the leading UK styles) is divided between general/nontechnical copy and scientific/technical copy. Neither of those guides says "such-and-such is correct or incorrect." They both just state a variety of things that are usually done. They both say that general copy usually uses commas and technical copy usually uses space or thin space. As for 4-or-more versus 5-or-more, New Hart's says that general copy usually uses commas for 4 digits or more (thus 1,000 and 10,000) and that technical copy uses thin space (thus 1 000 and 10 000). Butcher's says that general copy usually uses commas with either a 4-or-more scheme or a 5-or-more scheme (take your pick) but that technical copy usually uses a space and a 5-or-more scheme (thus 1000 but 10 000). Both guides state that whatever style is used in text, it should be overridden as needed in tabular matter to enforce decimal-place alignment (up and down the column). By now you may be wondering why the hell there isn't one simple rule instead of all that variability just described. The answer is that no single authority governs it in English, either UK English or US English. Only prevailing orthographic consensus(es) and house styles govern it. Welcome to the human condition—negotiations, power struggles, people who think that X is "wrong" when it's really not, people who won't agree to standardize on Y partly because they like Z better but also (although they won't admit it to others and possibly not even to themselves) rather more because they want to keep the guy who likes Y from being seen having his way and they want to claim that their way is better so that they can be seen having it and get to enjoy making guy Y bow to it. See also a century of wasting resources on anti-metrication "logic". Quercus solaris (talk) 22:41, 17 April 2015 (UTC)

The SI style (with thin spaces) is becoming more common in the UK, and is usually taught in schools, but people like to cling to the older thousands separator. Dbfirs 16:38, 10 May 2015 (UTC)

Potentially different decimal separators used for normal, monetary and version numbers

Some NLS systems allow to specify different decimal separators for different contexts even within the same locale:

• Numeric decimal separator - for "normal" numbers, typically a comma or dot, as already discussed in the article.
• Monetary decimal separator - for usage of numbers in conjunction with currencies, sometimes the same as the numeric decimal separator, sometimes the opposite of either comma or dot, sometimes another character such as the corresponding currency symbol. Example: In Portugual, the comma is the normal decimal separator, but the cifrão sign ($) was used in currencies instead of the decimal comma, as in 2$50.
• Decimal version separator - the decimal separator used in version numbers (if interpreted as decimal numbers), almost always a dot (even if the numeric decimal separator is a comma), but I've also seen spaces, hyphens and slashes. Example: In Germany, the comma is used as the normal decimal separator, but a dot is used for version numbers. (I've also seen this being implemented to automatically use either the same character or the "opposite" as the numeric decimal separator, dot or comma, but so far I have considered this to be a bug.)

It might be interesting for readers to find some further background on this in the article. Which conventions exist globally? Are there any standards for this? Are there even more such "contexts" where decimal separators, differing from the default ones in the corresponding locales, are used? --Matthiaspaul (talk) 01:42, 15 December 2016 (UTC)

The map is wrong for Spain. From 2010 the Real Academia de la Lengua recommends the usage of the decimal point. The CSIC style guide recommends it from much earlier. — Preceding unsigned comment added by 90.71.73.34 (talk) 22:41, 15 May 2017 (UTC)

The page for Set notation doesn't discuss why, but it uses commas to separate {π, 6, 1/2}. I'd assume there would have to be a difference for those that use a comma as this could also be written as {π, 6, 0.5} or {π, 6, 0,5}, in which case the comma becomes ambigious. — Preceding unsigned comment added by 80.193.174.53 (talk) 15:52, 24 May 2017 (UTC)

I think in general that is disambiguated by placing a space after the comma when enumerating the set. But I looked at a section of the French article, fr:ensemble#Ensembles finis ("Finite sets"), and there are a couple of uses that are without spacingh:

• la paire des éléments 1 et 2, notée {1,2}, ne doit pas être confondue avec le [[couple (mathématiques)|couple]] (1,2), qui a un ordre déterminé.
• The [unordered] pair of elements 1 and 2, written {1,2}, is not to be confused with the ordered pair (1,2).

This may just be a typo in French Wikipédia, though. The article gives no examples with decimal fractions. I checked German and Hungarian but the examples of set notation there are either with natural numbers, or with algebraic letters. Perhaps sets of real numbers are not commonly enumerated so the point is moot? 94.21.219.120 (talk) 15:47, 9 December 2018 (UTC)

Requested move 13 October 2017

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: not moved TonyBallioni (talk) 21:46, 20 October 2017 (UTC)

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Decimal mark → Decimal marks – This is a naturally plural topic; the article is not about "a decimal mark" or "the decimal mark", but about decimal marks as a class, which vary by language and usage contexts within some languages.  — SMcCandlish ☏ ¢ >^ʌⱷ҅_ᴥⱷ^ʌ<  21:18, 13 October 2017 (UTC)

Disagree. The argument made is not strong enough to rise to the level of exception in Wikipedia:PLURALS. For example, the page Dog is not about "a dog" or "the dog", but about dogs as a class, yet we use the singular form for the title. --Bill Cherowitzo (talk) 21:56, 13 October 2017 (UTC)

Disagree. There really only is one logical entity, which takes various forms. Imaginatorium (talk) 04:03, 14 October 2017 (UTC)

• Oppose – SMcCandlish is usually spot on, but not this time. It's about individual marks, not the class. Dicklyon (talk) 04:46, 15 October 2017 (UTC)
• Oppose Per User:Wcherowi._{ZXCVBNM (TALK)} 01:12, 16 October 2017 (UTC)

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The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

Namibia

On the website of the Namibian Government, they use the dot as decimal seperator: http://www.gov.na/population Makes sense to me, since they are an English speaking country. So I would ask to move Namibia from "countries ... with decimal comma" to "countries ... with decimal point" — Preceding unsigned comment added by 2003:c0:e3de:f775:39b7:19a1:cddc:d14 (talk) 00:15, 27 January 2018‎ (UTC)

Agreed, and changed. Batternut (talk) 23:19, 27 January 2018 (UTC)

Both comma and point are used, within gov.na and outside it. Status quo is preferable until better evidence is found. Or perhaps there should be a third category. — RFST (talk) 06:28, 28 January 2018 (UTC)

Yes, South Africa would also fall into a mixed category, judging by the comments at Wikipedia talk:WikiProject South Africa#Should South Africa articles use "continental system" numbers?. Perhaps a section entitled something like "Countries using Arabic numerals with both decimal comma and decimal point". Batternut (talk) 13:53, 28 January 2018 (UTC)

Perhaps, but that's rather a long title, and it seems to be a declaration that you have full freedom (without even so much as a style guide, see talk section about South Africa), so it should at least be worded differently. And how much divergent use is enough to put a country in this category and on a slippery slope? And is it really only by country, or also by language (a computer locale is first by language and only then by country, and maybe some information should be sourced from computer-related projects)? — RFST (talk) 06:39, 29 January 2018 (UTC)

You raise three good points. The section name is indeed terribly long. Since both current sections are in the "Hindu–Arabic numeral system" section, one option could be to strip out the implied "..using Arabic numerals...", giving subsections "Countries using the decimal point" ,"Countries using the decimal point" and "Countries using both decimal comma and decimal point".

Or perhaps another approach entirely - to replace both sections with a single table, one row per country, with a column list of "country", "decimal point usage" and "decimal comma usage". Ticks and crosses or some text equivalents would generally suffice; for countries using both though any kind of qualification could be added. For the South African example, in the comma column, we might mention the official position, while in the point column observing its predominance. Complicated cases could use section links to expanded descriptions lower in the article. Per language variation could also be mentioned in the table, and expanded upon below. Batternut (talk) 09:15, 29 January 2018 (UTC)

A single table probably takes too much vertical space and is still not very informative compared to a structure that would show the putative causes (luckily there's a picture, although it has Namibia in blue). There are already several countries mentioned in both sections (Canada, Luxembourg, Switzerland, perhaps more) with proper qualification; you could perhaps do the same with Namibia and South Africa. — RFST (talk) 15:21, 29 January 2018 (UTC)

That would probably be fine, potentially with footnotes. Batternut (talk) 16:30, 29 January 2018 (UTC)

Now in both lists, with qualification "(uses both marks)" and a reference for the decimal comma. Perhaps it would be useful to describe usage further, because references with decimal comma are far more easily found than for South Africa but perhaps also in a decline. — RFST (talk) 06:44, 4 February 2018 (UTC)

algol

"ALGOL ended up allowing different decimal separators"

Can this be true? It seems it would wreak havoc parsing argument lists to have commas in literals. (More likely they permitted different formats in i/o, not in the actual source code. ) Gjxj (talk) 14:22, 22 March 2018 (UTC)

Digit grouping and decimal separating aren't the same

I am confused. Why is "Digit grouping" a section under the article "Decimal separator"? The topic is about the separation of the integral and fractional parts of the number, not the grouping of the integer. —Wei4Green | 唯绿远大 (talk) 20:35, 10 November 2018 (UTC)

I was wondering the same thing. (There are several redirects to that section, too.)

The two are closely related, the symbol used for digit grouping must needs be different from that used as a decimal separator, so splitting the article may do more harm than good.

Treatment of the fractional part may also require grouping symbols. Strict SI orthography does, using a thin space as the group separator, but I have rarely seen it used in English-language texts, and this is not mentioned at the SI article. (See https://physics.nist.gov/cuu/Units/checklist.html item #16, "The digits of numerical values having more than four digits on either side of the decimal marker are separated into groups of three using a thin, fixed space counting from both the left and right of the decimal marker.") For quantities expressed in SI, it should be far more likely to have separators in the fractional part, since the integer part should be be expressed in terms of 10³ⁿ such that the integer part is never more than three digits, anyway.

It might be worth formally proposing a split. 94.21.219.120 (talk) 15:21, 9 December 2018 (UTC)

I, too, was wondering why the topic doesn't have its own page. Note that it gets its own page in some other languages' Wikipedias (e.g. in German), which could be drawn upon. Regarding the concern above that "two are closely related, the symbol used for digit grouping must needs be different from that used as a decimal separator, so splitting the article may do more harm than good": One option would be to leave a summarizing section that focuses largely on that relationship, but put a full article link at the top of the section. —Undomelin (talk) 22:25, 3 May 2022 (UTC)

Would the table on my talk page be a helpful addition?Lee De Cola (talk) 17:52, 7 January 2024 (UTC)

Austro-Hungarian Empire

Austro-Hungarian Empire and Austria prior to 1938 used · Dieſelmaus (talk) 01:55, 15 November 2019 (UTC)

Merge radix point into decimal separator

The radix point article starts like it is going to be more general than decimal separator, but it has practically no information about radix separators for other number bases, other than they may be used. Thus the information contained in the head section is basically a small subset of that contained in decimal separator.
On the other hand, the information in the body of the article is not about the radix character (which is how "radix point" is defined in the head) but rather on the representation of fractions in positional number notation. Therefore, that information should be merged into Positional_notation#Terminating_fractions, if it is not all there already.
--Jorge Stolfi (talk) 20:32, 4 July 2021 (UTC)

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Australia

It appears Australia has adoped the comma on the line and space for thousands. https://extranet.education.unimelb.edu.au/SME/TNMY/Decimals/Decimals/backinfo/overseas.htm Avi8tor (talk) 14:37, 8 January 2023 (UTC)

Informally Danes probably only use spaces for grouping

I haven't seen anyone using "." for grouping thousands in Denmark since I went to school, where it was taught. I doubt anyone uses it in real life, except when writing bills and such. 5.186.78.167 (talk) 11:32, 12 October 2023 (UTC)

Spain

Spanish Real Academia Española (RAE) recommend using a thin space as thousands separator, and a dot as decimal separator.

Usage of comma as decimal separator is discouraged, but also accepted, since using a space as thousand separator disambiguates its meaning. A dot is preferred to align with international standards.

However, this official rule is often not applied. Most people don't know about it or don't like it. Also it is common to find contradicting information (like this Wikipedia article, at the time of writing).

I think it would be nice to at least note in the article that there are conflicting versions and point to the official vs. popular formats.

Sources:

• Diccionario panhispánico de dudas: números
• Ortografía de la lengua española
• 20 minutos: Los números no se escriben como crees: la RAE explica cómo se hace y Arturo Pérez-Reverte da su versión

Gimix3 (talk) 11:02, 3 November 2023 (UTC)

That seems reasonable, and much of the above text could be used as-is, other than Wikipedia doesn't use contraction like "don't", the entire comment about "Most people" isn't encyclopedically relevant, and the citations would need to be done inline.  — SMcCandlish ☏ ¢ 😼  06:54, 4 November 2023 (UTC)

Dates and others

It is said that there is no separator used in writing years. But the usage is more complicated. Yes, when writing out the year in many dating systems AD, CE, AH, BP etc.for dates of historical interest, which happen to be confined to four digits or less, no separator is used. Thus 2024 CE or 2234 BCE. But when - rarely - there is a reference to a year using more than four digits, such as 20,000 BP, then a separator is often used. On a different topic, when a number is using a numeral in some systems, such as month. day, year, or a base 60 system (eg Babylonian or degrees minutes seconds) a separator is needed. It gets more complicated than this article touches on. TomS TDotO (talk) 04:47, 13 February 2024 (UTC)