Rated 4 out of 5 stars

Great idea! I use scrollable tabs and was always finding myself having to count through them to connect the number each was --argh! Now this does it for me. Kewel! And I often have way more than 9 tabs open, so the option to at least hotkey to like 8 more of them is a bonus.
Like another post mentions, I would like to see a hyphen " - " after the number. Or perhaps either a "." or a " ) " or a combination e.g. 24.)
I'm sure with usage, this will be less of a factor but it still seems like an optimal idea.

Also, as a heads up, the hotkey needs to be customizable/user definable. Not only does Alt+X conflict for me, so does the only other option, Alt+Z. [Alt+X opens the install add-on window; Alt+Z opens the Sage add-on sidebar.]
Optimally, I'd prefer either a context or icon option. Hence why I could only give 4 stars --I can't get to the other options to try them. :(
Thanks for taking my feedback & for the helpful extension. :)

This review is for a previous version of the add-on (0.6.3). 

Works just fine

Hello David,

Which version are you using?

Because in 0.6, there is a NumExt label control under "Tools" to active the command parse box

Also, you are able to set your customize shortcut keys, so instead of Alt+X, you can set Alt+Y or any other letters.

You may wanna have a look at the how to

http://numext.alouche.net/howto/

and look at the screenshots to see what I mean

http://numext.alouche.net/

Feel free to email me if you have any further questions.