The ALT+ trick has been available since the DOS days. I use it all the time to type the degrees symbol (e.g. 25°C - ALT+0176), the Greek micro as a prefix (e.g. µHz - ALT+181), a plus or minus symbol (e.g. ±3dB - ALT+0176) and more. Works in almost all PC applications.
A lot of these tricks have been around since time began ... the problem is that newbies don't know them...
...I think we would all be surprised to discover all of the little tricks and back doors that are available ... if only one knows where to look...
That video is great! For math formulas, you might find this useful. Microsoft OneNote (bundled with Office) has a nice “ink to math” utility. You can just draw a formula freehand using your mouse, highlight it, and convert it to a formatted equation. You can then insert that into a Word document if you wish. There is also an “ink to text” utility for converting freehand text to print.
In the old DOS days it was well nigh infallible. These days it depends on the font you're using - some seem to work and some don't.
Again in the old dos days (don't I sound like and old fart??) you could use this trick to get the single and double line box characters, and use them to make great looking menus.
Most symbolic math programs can output the results as both programming language code (C, Fortran, etc) and as TeX formulas. For instance, Maxima:
I generated a quick expression (Pade approximation of a Taylor expansion of a symbolic derivative, whatever), and right-clicked on it, selecting "Copy LaTeX', to receive:
I do not believe the current versions have standalone capability. However, I do know that in old, old versions (something like Win95 and/or Office 2003) I used to keep a shortcut on my desktop and could/did run it outside of Office almost daily.
Note the following sentence from the link below, "It can be used as a standalone program or it can also be used from within applications that support OLE as an embedded object."
If you haven't tried it yet, Open Office.org's Open Office Suite is great for formulas and equations which can be designed and inserted into documents, Power Point Presentations, Spreadsheets, Etc., all of which are included with the Open Office Suite which is Public Domain (note: free) software and in my humble opinion, much better than MSFT Office.