# How do you write a large number in a sentence?

I was there for 45,400,000 (forty-five million, four hundred thousand) seconds
I was there for 45,400,000, forty-five million, four hundred thousand, seconds?

• What kind of writing is it? A scientific article, a work of fiction? May 29, 2020 at 23:09
• Either way, having commas there - at least to me - implies that the "45,400,000" and the "forty-five million, four hundred thousand" are two separate things. The parentheses show that you're spelling out the number. May 30, 2020 at 0:55

For a scientific work, I would go with something more like scientific notation:

4.54 * 10^7 (four point five four times ten to the seven)

Many engineers prefer to use only power of three exponents (3, 6, 12, 21, etc...), so then it would become:

45.4 * 10^6 (forty five point four times ten to the six)

For something less formal (where it should be okay to only use one or two decimal places any way), perhaps:

45.4 million (forty five point four million)

Personally, I can't imagine an informal situation that requires a full long hand wording of a number unless, perhaps, for the purpose of some unique rhyming or prose cadence. In this case, it would be most important to write it in a flowing lyrical manner that 'sounds good' in context rather than adhere to strict grammatical conventions.

• The standard form for scientific notation is 4.54 * 10^7. The bit before the decimal point should be between 1 and 0.99... Jun 3, 2020 at 12:37
• @GarethN, scientific yes, engineering not. Engineering prefers factor-3 powers: 3, 6, 9 etc., which correspond to named numbers/prefixes (k, M etc.)
– Zeus
Jun 5, 2020 at 2:35
• @GarethN, (& Zeus), Erm yes sorry, you are both correct. I fell victim to my own engineering background in the answer. I shall upadate to highlight this distinction. Jun 5, 2020 at 7:36

I would probably do either just the number or just the words. My fourth grade teacher told us that numbers under fifteen have to be told with words, and it doesn't matter for larger numbers. I'd probably go with just words.