@Isuwen said:
Those are not things from America. The proper usage here IS to replace and with the decimal place. However, you also must supply the fraction. 'one hundred and two' is not correct. One hundred and two tenths is.
Think about what you just said logically. If the "and" is working as a decimal place then you don't need to supply a fraction as you know that whatever comes after it is after the decimal place. Eg, Two hundred and one, 200 AND 1, would be 200.1 *if* it worked that way. The correct way that the "and" operator works is that you add the two sides together, eg Two hundred and one becomes 201.
Otherwise if you replace the "and" with a decimal place, then with your example of one hundred and two tenths, 200 AND 0.2 you would get 200.0.2 (makes no sense right?), or if we were to ignore the extra decimal place you would get 200.02, not two hundred and two tenths.
The function of "and" acting as addition is highlighted by previous examples, eg, one hundred dollars and two hundred cents. 100 cents = 1 dollar, lets convert them to the same units. 100 dollars and 2 dollars. Can you honestly tell me 100.2 is one hundred dollars and two hundred cents? Obviously people won't normaly say two hundred cents, but you know, it's an example which shows how the replace and with decimal point breaks down. So it makes more sense just to use it as addition. Get the coins out if you need to, I want you to figgure out how one dollar and five hundred cents becomes 1.5 dollars and not 6 dollars (or for that matter one dollar and 5 dollars. I'll trade you 2 dollars for one dollar and five hundred cents, lol)
This exact same logic can be used for any other numbers, just replace "dollars" with "units", you have to specify a different unit (or fractional number) to get that decimal place.