Good but could be better
Other than that very useful!
Response from developer
Hi, we have changed the keyboard to use the number pad with decimal point in one of the previous versions after receiving your request. There is now also a button at the top of the keyboard that lets you put a - sign in front of the number (or remove it) when pressed. This will put a negative sign in front of the number after you have entered the first digit of the number. If there is a negative sign and you want to remove it, just press the button again and the negative sign will be removed from that number.