Making a <div> element without a newline before it?

<div style="display:inline-block">4</div>

or

<div style="display:inline">4</div>

It really depends on how you want to use the div container. It might even be more practical (for the latter example) to use a span if you do not want a block element.

Though you can use a <div> to do that, most people would recommend you use a <span> instead.