Here's my take on it as a Maths and Statistics graduate.~ Usually when we talk about fractions with large numerators or denominators, we can say: 1/5 One over five One divided by five a fifth/one fifth 3/5 Three over five Three divided by five three fifths 25/37 = twenty five over thirty seven twenty five all over thirty seven twenty five divided by thirty seven twenty-five , thirty-sevenths Simply because once you start working with large numbers, it can be confusing when I want someone to understand (when I'm talking over the phone): 234/478. 'two hundred and thirty four' over 'four hundred and seventy eight.' 'two hundred and thirty four' divided by 'four hundred and seventy eight.' Of course you can also say: two hundred and thirty four , four hundred and seventy eighths Saying the over/divided words in English makes it clear that it's a fraction. A number such as 0.749 is pronounced as: 'seven hundred forty nine thousandths' Which people may get confused with. (simply because in maths/science/engineering it may be useful to work in fractions or decimals.) Personally, I think decimals is harder to pronounce (even for English natives). I hope that helps!