There are two valid options, in my opinion, two choose as global standards. The first option is the idealistically pure one because it uses existing punctuation to more accurately convey the relationship between the individual digits within a large number. The second option is basically an inferior standard, but it is one that is most widely in use now, so the transition costs would not be anywhere as large as the first option would entail. Nevertheless, this option is logical enough that we would benefit from the elimination of many other less logical systems.
Option #1 – The Most Logical Option
Blank Space Number Separator
An alternative numbering format, which may be more logical would be the International System of Units (SI) format in which the thousands separator is merely a single blank space such as the spacing between words, but can also be a smaller spacing. This may make more sense because a conventional comma used as the thousands separator may imply too much distinction between the number, like a comma would when describing, for example, a large, red, sleek car. Yes, all words describe the car but they are completely different characteristics. With long numbers, all the numbers are actually part of the very same number. Digits between number separators do not signify a different characteristic of the number, they are basically just a part of the name of the whole number itself. These number separators (blank spaces in this proposal) merely serve to make it easier to read, a function that could well be accomplished by single empty spaces.
Apostrophes should also be used after (to the right of) the decimal mark to separate hundredth, millionth, billionth, etc. (Ex. 123,456,789.012,345,678).
Reluctantly Keep the Decimal Period
Following this same logic, the decimal point would appear to indicate a break between one complete thought and another, as it does in ordinary sentence structure. But a decimal written within a number (between whole numbers and decimal fractions) merely indicates a change in scale while still describing the very same number. Currently, a decimal point used within a number indicates merely the transition between whole numbers and decimal fractions. But the decimal fraction is an integral part of a number, therefore it is nothing at all like a separate thought, or even a related item. It is actually part of the number, just like a letter is part of a word. In words like x-ray, ex-wife, day-to-day, ill-fated, and others, the hyphen is used to indicate a direct, integral relationship between the words. This is precisely the relationship between a whole number and its decimal fraction. So maybe a hyphen would be most appropriate. But since a hyphen is commonly used to indicate a range of numbers (such as (the car was 10-20 feet away”), it would not work as a decimal. An additional downside to using a hyphen would be the difficulty of verbally stating numbers with decimal marks in them, such as 1.2 billion (one point two billion). Under this proposals, this number would be written as 1-2 billion. Apart from the range confusion indicate above, there would be a verbal and written discontinuity since it would be impossible to change the verbal “point” when referring to numbers. That would be unacceptable. An interpunct or interpoint, or raised dot, or middle dot as it is often referred, has been used in the past as a decimal mark, especially in British English, but because of it confusion with the mathematical character for multiplication, it had not been selected as the standard decimal mark. Therefore, it is necessary to stay with the conventional full stop period as the standardized decimal mark.
Option #2 – The Less Optimal Option
The worldwide standard for the use of punctuation within written numbers should be as follows: a period should be used to separate whole numbers from decimal fractions and a comma should be used to separate sets of thousands, millions, billions, etc.
Just like a period at the end of a sentence indicates the end of a grammatical unit and the end of one complete thought (essentially a separation in structure), a period between whole numbers and decimal fractions indicates a separation and division of the structure and meaning of the number. Whole numbers indicate a quantity of complete/whole units; decimals indicate only a fraction of one unit.
Also as in a sentence, commas are used to indicate a separation of ideas or elements within the structure of a sentence. Commas used in numerical writings should only be used to separate within the structure of the number, such as to separate the number sets of thousands, millions, billions, etc. The use of commas in this way, not only makes it easier for such numbers to be read, but also keeps with the logic of commas being used to separate between related items. Their use in this way also instructs the reader to pause as a large number is read. The alternate method of numerical writing, namely, including an empty space in places where commas would otherwise go, should not be used because this would imply too much of a separate meaning between the number groupings. This would also cause greater confusion and difficulty, especially when writing numbers by hand. Commas should also be used after (to the right of) the decimal point to separate hundredth, millionth, billionth, etc. (Ex. 123,456,789.012,345,678).
Long-Scale Numbering Nomenclature
Additionally, ‘long scale’ numbering nomenclature (thousand million, milliard, thousand billion, billiard, etc.) should be prohibited in favor of ‘short scale’ numbering (our conventional numbering nomenclature (thousand, million, billion, trillion, quadrillion, etc.)).