I have this issue too. When I enter a negative number I start with = before I enter the minus sign!

Thanks graendal -- an imperfect solution to a problem that only started recently. Still, better than the routine I was going through.

This is not just Mozilla problem, but same for all browsers. You can use the minus key on the numpad of your keyboard, but not the dash key. Unfortunately, if you are not using full-size keyboard, you can't easily access the numpad minus.

I have been using this method myself on my laptop: hit any number/letter, then quickly hit backspace and then dash. This for some reason lets the dash key to enter as a minus sign.

Graendal's way is much better, but still, I don't understand why Google decided not to allow the dash sign to be used as a minus sign.

tigerleap wrote: This is not just Mozilla problem, but same for all browsers.

Well, it's not an issue on Google's Chrome browser! But it is on Firefox and Safari. Coincidence? I think not.