The need for interactive specification and editing of numbers arises in almost every geometric application. Current user interface toolkits provide a very limited set of User Interface Devices (UIDs) for number specification; usually only a text UID and a slider UID are provided. We present VigNumber, a UID for numbers. VigNumber allows exact specification of both number and grid increment using the keyboard, single digit increment/decrement using the mouse, and rapid and exact navigation using the mouse and the grid increment. The user controls both number and grid parameters in the same context.