There is a commercial product called GrindEQ which can also convert math. Another option is to import your LaTeX into LyX, and output as a Word document.
Aside from the free solution using LyX, you can use LaTeX2RTF, which works okay. Also latex2doc which is a bit more sophisticated. Lastly, there is Pandoc which is a more universal converter.
Your mileage may vary, which is why I am inundating you with choices.
You should be able to cut and paste mathematics from your web browser to Word (or any of the Micorsoft Office suite). Unfortunately at present you have to make a small edit but any text editor will do for that.
Given
x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}
Make a small html file that looks like
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript"
src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>
<title>tex texample</title>
</head>
<body>
$$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$$
</body>
</html>
View that in a web browser and select "show MathML as/MathML Code" from the right menu:
Select the MathML text from the popup window.
Normally you can paste MathML in to word but for various reasons you need to give Word a hint in this case, so first paste it into a text editor and add the line
<?xml version="1.0"?>
to the start:
Then cut out the edited text and paste it into Word (any version since 2007).
Note the result is a fully editable Word Math Zone, using scalable fonts, not an image.
I used MathJax in a web browser for the initial TeX to MathML conversion as it is the easiest to set up, there are other alternatives. Also, to make it simple, I described the process in terms of cutting and pasting, which works well for one or two expressions but clearly not if you are converting thousands, however the process can be automated in various ways.
Best Answer
You can use TeX4ht to convert it to ODF. The command is thus:
See the documentation of TeX4ht here: http://tug.org/applications/tex4ht/mn-commands.html#QQ1-9-38
Then you can use any ODF-compatible word processor (LibreOffice, OpenOffice, and even MsWord) to convert it to .doc or .docx.