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.