Why do people put commas in numbers?

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Behodar

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#103526 9-Jun-2012 09:14

When i was growing up, I learned to write large numbers using a space to separate thousands (such as 10 000 for ten thousand). I learned this from my dad, who is an engineer and uses a space in accordance with the relevant New Zealand Standards.

Of course, in the "real world", people tend to write ten thousand as 10,000. Where does that notation come from? Is it an older system that's prevailed after the introduction of the NZS or SI?

I've been wondering about this for a while, and Google isn't finding much of use :P

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#638130 9-Jun-2012 09:20

While this doesn't directly answer the question it does provide some info

http://en.wikipedia.org/wiki/Decimal_mark

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Digmarx

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#638137 9-Jun-2012 09:40

I'm American, and I use commas to separate numbers. My understanding is that it's one of several ways to aid parsing large numbers. 1,234,567,890 is easier to read than 1234567890. Various European countries swap the use of comma and point, so I would write 12,345.67890 and a German person would write 12.345,67890

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#638138 9-Jun-2012 09:40

Interestingly, a number of countries use the reverse of our "common" notation. i.e. where we might write 1,234.56789, they will write it 1.234,56789 - doesn't answer the question though sorry!
[edit] Snap! - despite both posts being 0940, I came second!!

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#638140 9-Jun-2012 09:43

because not everything you grow up with is the entire answer ... there is always more to something you thought was absolute ... and there usually is more than one way of doing something ...

like a hypothesis in the UK, an hypothesis in the US

like stadia in the UK, like stadiums in the US

like hung in the UK, like hanged in the US

i presume there is more to whatever NZS or SI in this planet

for the above options though, NZ adopts either and both are correct in this country. not so in the UK, not so in the US, but i guess NZ needs to keep their important allies happy

Behodar

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#638141 9-Jun-2012 09:47

I'm aware that other countries do it differently, I was just trying to figure out why we have two systems here. If both are still correct then I won't complain :)

meesham

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#638142 9-Jun-2012 09:48

joker97:
like hung in the UK, like hanged in the US

My understanding is this is the same everywhere:
hanged - only used when you hang a person
hung - for everything else (eg you hung a picture)

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Behodar

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#638143 9-Jun-2012 09:51

meesham: My understanding is this is the same everywhere:
hanged - only used when you hang a person
hung - for everything else (eg you hung a picture)

That's my understanding too, and my UK Oxford dictionary confirms that it's hanged for a person and hung otherwise.

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#638152 9-Jun-2012 10:34

Behodar:
meesham: My understanding is this is the same everywhere:
hanged - only used when you hang a person
hung - for everything else (eg you hung a picture)

That's my understanding too, and my UK Oxford dictionary confirms that it's hanged for a person and hung otherwise.

oops my bad ... originally they were interchangeable but it has evolved into these meanings now - and no US/UK tension for this particular word

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#638160 9-Jun-2012 10:46

I don't use commas either. I remember at school a techer telling me that I should, but she couldn't actually give a good reason why.

John2010

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#638217 9-Jun-2012 12:59

Behodar: ...I learned this from my dad, who is an engineer and uses a space in accordance with the relevant New Zealand Standards.

Of course, in the "real world", people tend to write ten thousand as 10,000. Where does that notation come from? Is it an older system that's prevailed after the introduction of the NZS or SI?...

I didn't know there was any NZ Standard that stipulated that a space was the "correct" or "desired" style for the thousands separator but would be interested in any reference to them? SI, as far as I know only state that a space may be used instead of commas or periods for clarity - it is certainly not stated as being the "correct" practice. So as far as I see, any of the three options is fine.

I have regularly worked closely with professional engineers of all ages in NZ and in many other countries for near on 40 years and do not recall any using anything other than commas or periods (depending, in the main, on country). But there again if someone had ever used spaces along the way it likely would not have stuck in my mind.

Personally, I use commas but that out of habit (my first degree is in physics, where one becomes used to seeing both commas or periods).

EDIT: Fixed overwrites due to accidental hitting of "Insert" key during original writing :-(.

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#638225 9-Jun-2012 13:26

See below for extract from the SI brochure (8th Edition). I guess the important thing is that however it is presented, people know what you mean!
-----------------------------------
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.

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. 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. 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.

---------------------------------------
Apparently the ISO standard 31-0 says something similar (ref: http://www24.pair.com/glyptica/ThousandsSeparator.html)

To facilitate the reading of numbers with many digits, these may be separated into suitable groups, preferably of three, counting from the decimal sign towards the left and the right; the groups should be separated by a small space, and never by a comma or a point, nor by any other means.

For what it is all worth!!

EDIT: sorry - didn't come out all that clearly when posted!

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mattwnz

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#638233 9-Jun-2012 13:59

We were told it was required at school. It does group them together well too, so you can easily see whether the number is millions, billions, trillions etc. 1000000000 is a lot easier to read and know what the number is when it is displayed as 1,000,000,000, otherwise you have to count the zeros. A gap is ok, but it could be confused for two different numbers.

For your information, if you type a number into an iphones caluculator, it wil insert comas for you, so it is relatively common for numbers to be displayed that way.

John2010

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#638241 9-Jun-2012 14:12

Well, see something new that is ignored every day

.

The BIPM recommendation must be one of those things taken notice of by few in that matter. Just done a quick check of styles and "Nature" magazine (which one would hope uses that which is the most "correct"

) uses commas as the thousands separator, as do National Geographic and Scientific American among the more populist, and Time among the media (if I recall CNN uses commas too).

Maybe is of the likes of newton metre which is supposedly to be written n dot m (sorry not goin' to work out how to do the raised dot in the middle) or n m (with a space) but which is mostly always written nm.

I do notice that at least the popular text Physics for Scientists and Engineers, Serway & Jewart uses spaces as the thousandths separator for the decimal parts of numbers (but I think mostly or only scientific notation so no need for thousands separator).

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#638252 9-Jun-2012 14:41

John2010:
Behodar: ...I learned this from my dad, who is an engineer and uses a space in accordance with the relevant New Zealand Standards.

Of course, in the "real world", people tend to write ten thousand as 10,000. Where does that notation come from? Is it an older system that's prevailed after the introduction of the NZS or SI?...

I didn't know there was any NZ Standard that stipulated that a space was the "correct" or "desired" style for the thousands separator but would be interested in any reference to them? SI, as far as I know only state that a space may be used instead of commas or periods for clarity - it is certainly not stated as being the "correct" practice. So as far as I see, any of the three options is fine.

I have regularly worked closely with professional engineers of all ages in NZ and in many other countries for near on 40 years and do not recall any using anything other than commas or periods (depending, in the main, on country). But there again if someone had ever used spaces along the way it likely would not have stuck in my mind.

Personally, I use commas but that out of habit (my first degree is in physics, where one becomes used to seeing both commas or periods).

EDIT: Fixed overwrites due to accidental hitting of "Insert" key during original writing :-(.

to paraphrase you are saying

"your dad is wrong

" ?

Behodar

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#638254 9-Jun-2012 14:54

John2010: I didn't know there was any NZ Standard that stipulated that a space was the "correct" or "desired" style for the thousands separator but would be interested in any reference to them?

I've seen the document but couldn't give you the number of it. Maybe next time I'm at the parents' place I can dig it out but I don't expect to be there any time soon.

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