Some Android devices do not give the possibility to enter a negative number using the Number-widget.
No MoreApp account yet? Sign up here.
When filling in a form, and clicking on a Number-widget, the standard numeric keypad automatically pops up on your device. This saves some extra seconds of your valuable time. When some Android users open their numeric keypad there is a chance that there is no minus sign ( - ) available on the numeric keypad.
The solution for this is: Replace the Number-widgets for Text-widgets.