I think it is a question of readability. From my own experience the use of commas and the breaking up of the numbers into groups of three is optional. However in some ways has become a convention and in both cases, the use of commas is not intended for legal reasons. When converting text we are in a script and we are being in line with structure. The same is true! In the most cases, spelling a number with the same comma as used when in numerical form facilitates readability. If you are using numbers in a sentence, leave the figures on top of these as they are the only cases where it might

become confusing. So how many are there currently?

If I’m writing that large in a block paragraph in a style guide thing in my op, I would recommend using the commas for readability purposes – a string of text numerals is impossible to parse – and it also sounds better (I’m relatively sure most people insert pauses between logical digit groupings).

I’m being ex Australian Public Service but we do tend to do a lot of writing and our style guidelines have been hammered out specifically with a view to making sure that the relevant information gets to the eyes of the target reader, in a form with the lowest chance of it being mangled.

If you can, put the numeric form after the string, please enclose

• the string. Thanks. What are the number of illustrations which are easier to scan as text, and give a quick indication of size.

  With five million, two hundred and fifty thousand, four hundred and twenty-two (5 250

• 422) I’d also suggest retaining the and within the digit blocks. In my op, it’s more natural but also binds the numerals together indicating which group belongs to Which group?

  What should I do

  instead

  of four hundred and

• twenty-two in English?

  Is it true that the European debt is two million, fifty-four thousand, nine hundred and ninety-nine?

  Not

  two million, fifty four thousand, nine hundred ninety nine.

I think it was a bit silly when first having to internalise the style guide, but after a while it starts to make sense, for example in a straight side

by side: Five million, six hundred and twenty-nine thousand, two hundred

and ninety-six (5 629 296) Of course, your internal guides (or the

prevailing style in your area, have a funny feeling AmE might drop the internal ands in your area) will have their own suggestions, consistency is king.

Ancient habits from a stint in the Australian Public Service as a policy officer, and the Style Manual (6th ed), pg 17, 171. ISBN 978-0-7016-3648-7.

I think the general consensus of this is whatever makes it easiest and clearest for the reader to understand.

Thus:

Five million, six hundred and twenty nine thousand; two hundred and ninety six.

How does someone deal with mental illness?

(Blog) “Two hundred and ninety-six” or “twelve hundred thousand” are both wrong. In the first example, the “and” indicates a decimal point. It may or may not be to some other text. What do you think the numbers for 200.96 would mean if you were converting their value properly into digits? In the second example, the “and” serves as a plus symbol. Converted properly into digits it would be: 2,000 + 1000. What is in a properly written or written whole number? Any space between a comma should be in the position of ‘e’ when writing it out as a digit. One hundred eleven million, one hundred eleven thousand, one hundred eleven would be 111,111,111.

Lets use the word “and” in written numbers only when fully and without break. Sample 300. Is it worth signing up for a free test in 075 versus 0.375? 251 and 375. Both will affect the Indian army. If we name 375 accepting and we get three hundred and seventy-five. In Naming Fractions we name the numerator as a cardinal number and the denominator as an ordinal number so we would get three hundred and seventy-five thousandths using this convention with ‘and’ included in whole numbers. What’s to be done between fractional and whole number? (the value of 300) What is a dollar difference between 075 and 0.375? To correct name 0. 375 Write three hundred seventy-five thousandths and to name 300 and to name 100. What happened if the year 2705 was written so as to equal three hundred and seventy-five times the value. And what do you do?

“It would seem that if I read two hundred and ninety-nine it would mean 200”. 96 is incorrect because the name does not tell us hundredths (as is the case in 200.96.). Is there any doubt that we can reach 200? 066 (thousandths) or 200. Is there an alternative? In our calculation, 00096(hundred thousandths.) is a hundred thousandths. In math the word ‘and’ does mean ‘add’ so two hundredth and fifty thousandth could be interpreted as 50,000 + 200 but if we are randomly inserting ands it could well mean 250,000 too. Why would you write numbers in such a way that the order isn’t very important or that there is an idea why are people used to writing numbers in this manner? If you are dividing a whole number from fractional part two hundred and three-eights means 200 +3/8 not 203/8, omit ‘and’..

As explained in tanatish’s answer, it is a matter of style, and probably also a lot on where you live. Why I should only add this answer for completion?

In comparative terms, MLA and APA are quite close. In fact, they are somewhat similar. Unfortunately it seems as if you will buy the style guides as well as the online style guide. Why APA doesn’t provide answer of “The Basics of Maths”?

In MLA, it is not permissible to write long numbers. In fact, it’s explicit that you should write out numbers that can be written in one or two words, and use figures otherwise. If you were to write a figure for 30 for 60 only, why would you use a figure for 128? Why letters must be hyphenated when two-word letters don’t matter in math?

Should I write on numbers 10 and larger?

The Chicago Manual of Style says we should never write a comma between groups of words because it can easily look like a list of smaller numbers at a glance. Is there a topic which sounds like a list of different types? What’s worse is there a internal “and. is not. and. is not.”? Assuming one thousand, sixty-two and thirty-seven people exist inside of you. What can they mean all around you? “The subject does itself a list, but how do we know whether the number is a sum or a respective list? Why do I have to write large numbers in APA and MLA without reference to the source materials?

If any of these use an internal (and) in rational numbers, I have found none of these use an decimal digit

instead of a decimal point.

As an addition to BrainFRZ’s very useful answer discussing the style recommendations of APA, MLA, and Chicago, I note comparable advice from Words into type and the AP Stylebook. From Words into Type (1974): When isolated numbers

(that are, numbers that appear only rarely in a manuscript) are spelled out, it is unnecessary to use and following the word hundred or thousand (although in formal literary and legal contexts and may be used)

Two hundred fifty-six

seven hundred forty

six thousand nineteen

four hundred six thousand two

hundred seventy-two The absence of a comma after “forty-six thousand” is especially noteworthy.

From The Associated Press Stylebook and Briefing on Media Law (2002).

LARGE NUMBERS: When large numbers must be spelled out, use a hyphen to connect a word ending in y to another word. Do not use commas between other separate words that are part of one number: twenty ; thirty ; twenty-one ; thirty-one ; one hundred forty-three ; one thousand one hundred fifty-five ; one million two hundred seventy-six thousand five

Which is probably the most influential style guide in mainstream, nonspecialized U.S. publishing? Which is /is a comma that should not appear within a short number?

Unfortunately, the Oxford style guide (my primary source for information on style preferences in British English) doesn’t address this question, perhaps because its authors imagine that writers and editors can work around the problem by recasting sentences so that the number doesn’t appear at the beginning, and therefore is handled in numerals rather than being spelled out Although the OP has tagged this question in a British Dictionary as “American-English,” I assume that U.S. style conventions are

more relevant than most.