How numbers should be grouped, using dot (.) or comma (,)?

Question

Example:

5.000.000 or 5,000,000?

Is both of them is right? Or not? Probably each have different purpose for the different case?

10 pts for good or detailed answer.

Answer 1

the choice of the thousand separator will actually depend on the choice of the radix point (the decimal point).

In US and most Eastern countries, the decimal separator is a dot, and thus the thousand separator is a comma. It reverses in other countries.

d:

Answer 2

It really depends where you are from which you use. However, In the US we use commas for that notation since we use the decimal as a seperator between the integers and the fractional component of numbers.


In the Middle Ages, before printing, a bar over the units digit was used to separate the integral part of a number from its fractional part, a tradition derived from the decimal system used in Indian mathematics[1]. Its regular usage and classification can be attributed to the Iranian mathematician Al-Khwarizmi. Later, a separator (a short, roughly vertical, ink stroke) between the units and tenths position became the norm. When this character was typeset, it was convenient to use the existing comma (,) or period (.) instead.

In France, the period was already in use in printing to make Roman numerals more readable, so the comma was chosen. Many other countries also chose to use the comma to mark the decimal units position[2]. It has been made standard by the ISO for international blueprints.

However, English-speaking countries took the comma to separate sequences of three digits. In the United States, the period (.), which is called a "stop" or "full stop" in some other countries, was used as the standard decimal separator. In the nations of the British Empire, although the period could be used in typewritten material, the point (middle dot: ·), which can also be called an interpunct, was preferred for the decimal separator in technologies that could accommodate it.[3]. This had the advantage of reducing confusion in the countries that used the period to separate groups of digits and it was generally clearer in handwriting (particularly when writing on a dotted baseline as on many forms). However, as the middle dot was already in common use in the mathematics world to indicate multiplication, the SI rejected this use of the middle dot as the decimal separator. However, the use of the period as decimal point was not banned. British aviation magazines thus switched to the US form in the late twentieth century. When South Africa adopted the metric system, it adopted the comma as its decimal separator. The auxiliary language Interlingua has used the comma as its decimal separator since the publication of the Interlingua Grammar in 1951. The constructed language Esperanto also uses the comma as its official decimal separator.

In the Arab world and Iran, where Arabic digits are used for writing numbers, a different character called momayyez — which is written like a forward slash — is used to separate the integer and fractional parts of numbers. To separate sequences of three digits, a comma or blank space may be used; however, this is not a standard. In Persian, there is a small difference between the "comma" character used in sentences and the comma-like character used to separate sequences of three digits.[1]

The separator in non-decimal numeral systems may be referred to as a radix point.


[edit] Thousands separator
Numbers with many digits before and/or after the decimal separator may be divided into groups of three, starting from the decimal separator in both directions. The symbol for this is called the thousands separator or, more generally (see India below), digit group separator. If the decimal separator is a point, the thousands separator is often a comma or a space. The latter is recommended in the SI/ISO 31-0[2]; when a space is used, it is often used after the decimal separator too, thus "1 234.567 89". If the decimal separator is a comma, the thousands separator is often a point or a space. Notations like "12,345", "12.345", "12,345.678", and "12.345,678" are ambiguous if the notational system is not known.

Answer 3

Apart from all other relevant considerations, There is a qualitative factor: if you are talking of money, say, then the dot is required to separate Rs. and Paise (indian context), and so on for other currency denominations! The comma then groups the hundreds or thousands, for the same denomination, before the dot comes in to separate the different denomination!

Answer 4

5,000,000 would be right, every 3 numbers get grouped, only if its an even amount of digits tho, and only would 5.000.000 be right if you were talking about decimals, or using long division, in algebra. 5.000.000 sounds like "5" because in algebra u take away all zero's (usually) but 5,000,000 sounds like "5 million" their is a diffrence in math. its hard to explain i did my best lol.