The Doctor has spoken

After Chris' complaint on 1/3 about my use of "and" in the year, I wrote Dr. Math.

"I have a friend who takes issue when I say the year as: two thousand AND ten.  She believes that this implies a decimal, thus reading it numerically as '2000.10'. Instead I should be calling the year 'two thousand ten'. Is she correct, because I prefer to always be correct!"

The Doctor wrote:

Hi Jean,

Normally, 'and' comes between the whole and decimal parts of a number, e.g:  339.45 = three hundred thirty-nine and forty-five hundredths. Many people will put in a gratuitous 'and' after hundreds, e.g.:  339 = three hundred AND thirty-nine, but this is incorrect.  Although 'incorrect' may be too strong a word.

It's not the preferred way of expressing it.  But 'not preferred' isn't the same as 'wrong'.  In sort of the same way, people from New York will often say something like 'Me and Tom went to get pizza'.  I mean educated people, too - people with graduate degrees.  Published authors.  You can insist that

it's 'wrong', and they can insist that it's 'regional'.  There's no clear winner in this kind of argument.

On the other hand, I don't think it's reasonable at all to insist that the 'and' implies a decimal, because there's no way to know what decimal is implied unless a denominator is specified.  That is, would  two thousand and ten mean two thousand and ten hundredths (2000.10) or two thousand and ten thousandths (200.010) or two thousand and ten ten-thousandths (200.0010) or two thousand and ten hundred-thousandths (200.00010) or something else? That is, if you're including a decimal, you need to say 'and' to make it clear where that starts; but just because you put 'and' in there doesn't mean there's a decimal.  (When it rains, I roll up the windows in my car; but if I put the windows up, it doesn't mean it's raining.)

My advice is to just say what your friend wants to hear when she's around, and do what you like in other situations.  :) Does this help?

- Doctor Ian, The Math Forum

Why, yes, yes it does!  I believe I am correct and in  a twisted sort of way, so is Chris.

Signed,

Mama

January eleven, two thousand and ten.