Bleg: a LaTex problem (updated x2)

A question for the LaTex gurus out there. How do you get equations numbers of the form "page number.equation number”. Is there a way to set things up so the equation command numbers this way automatically?

I'm sure someone must have written a style file or something that does this.

Thanks.

Update: Via twitter comes this answer from David Winter

@EricCrampton @psw1937 @ATabarrok \numberwithin{equation}{page} from amsmath. #veryUsefulTimeSink
— David Winter (@TheAtavism) January 3, 2015

And indeed putting the \numberwithin{equation}{page} command in the preamble of your document, assuming you are using amstex, gives the desired result. The only problem I have found with it is that it sometimes miss-numbers the first equation on a page if that equation is at the top of the page. In some cases it carries over the equation numbering from the previous page. But you can find ways around this.

Its a lot better than what I had before.

Thanks David.

Update 2: Another suggestion I have been given is to use the "perpage" package with the commands

\MakePerPage{equation}
\renewcommand{\theequation}{\theperpage.\arabic{equation}}

in the document preamble. This works as far as I can tell.