There’s been some discussion about the correct way to write numbers today at work. Here’s my take on it:

And with the hidden chars turned on:

 

I’ve always been surprised that people still use a comma to separate thousands as they’ve been deprecated since the ’70s!

In different countries around the world, different symbols are used to mark the decimal part of the number and to separate the thousands. In Australia today we use a decimal point and a space (as a thousands separator), but until the 1970′s the accepted notation was a comma as a thousands separator.

We ran into this on a competition we did a while ago, and it turns out that the correct thousand separator is a thin space.

It’s   in html and in InDesign you can get to it with the shortcut** [ctrl]+[shift]+[alt]+[m]** or through the Type → Insert white space → Thin space menu.